The flow to this mission is a little unique, you have a specific stationary objective you need to get to before you really get cracking on the mission itself. There are a few ways in and a few ways to kill the three targets. Note that I’m just going to assume that you want to kill all three. It’s basically just free money and apparently the game randomly decides which of the three will be your main target, so you have to be ready for any of them.
Lots of options for disguises actually.
Patients robes aren’t too good and you’ll probably want to ditch them fast. They’re basically free though and if you take them then your suit is in an easy to find spot in a safe area.
The therapist clothes are also nice if you can quietly take out a therapist or steal them from a side room. They don’t give you much extra access, but they’re nice.
The security guard clothes are basically vital unless you’re really good at sneaking. I’ll help you pick up a set easily.
The orderly clothes are the grand prize. You get 100% freedom in these.
The VIP guards aren’t that helpful, since they don’t have more authority than the therapist.
You shouldn’t have to do any shooting. Having a pistol is nice for taking human shields, but you can just steal one from a guard’s body or the guard station. They’ll also search you going in and there isn’t any way to hide it. So you’ll either have to sneak in with a gun or try to throw it over a fence before going inside.
Nothing is actually too tricky about this one. Just take it slow and get used to the map.
Flatline - Entering the Clinic
There are three easy ways into the clinic.
The first is as a patient. I like this one, since it feels more unique to Hitman. It’s a little harder to actually do it though since you basically need to grab a keycard at some point and take out a security guard. We’ll fool with that in a minute though.
There are two options to get in as a patient. The first is easy. Look up on that balcony/overhang. That guy up there is having a last smoke before entering. You can sneak right up behind him and snatch his admission papers from the bench. Walk up normally though. The security guards will not be thrilled to see you climbing up. You can just run up the hill to the left to save time. Walk into the clinic and hand the nurse the admission papers. She’ll wave you into a changing room. Stash any guns and change into the robe. You’ll be frisked on your way into the clinic, but you should be fine.
You can also just steal patient robes from a guy sneaking a smoke by the dumpster. It’s remote as it is, and he should hide behind the dumpster when the patrolling guard comes by. Take him out, steal his clothes and then dump the body in the dumpster when the guard isn’t around. Walk into the clinic normally.
Note that once you enter, you should go up to the therapy offices. One of the doors should be open. Walk inside and look on the dresser. There should be a bag with a therapist’s outfit inside. Put it on to gain access to the majority of the clinic.
You can also sneak into the clinic. You can climb up a drain pipe to get onto the roof of the clinic. Walk to the left and stay low. Keep an eye out for a nurse and a VIP guard that take smoke breaks on the balcony. Wait for them to go back inside and then slip past. There’s a large dumpster that should serve as a landmark. Climb down the drain pipe near it and find the utility box. Pull the circuit breaker out and hide. The security guard on duty will come out to fix it. Sedate him and then steal his clothes. Dump the body and go inside. Note that you’re actually right where you need to be for the next part.
Flatline - Rescuing Agent Smith
Okay, well we need to get into their heavy duty ward. The only way in is with a keycard that is lying on the security desk outside it. As I said, if you sneaked in, then you’re already here.
If not, walk to the right from the entrance and look for the security station. Wait for the VIP guard to not be outside the door and then sneak inside. Sedate the guard and dump his body outside, preferably in the dumpster if you don’t mind a slightly long drag. I guess you could also slip past, go outside and break the utility box. If you grab a pistol on your way out then you can just take him as a human shield and save a sedation shot.
I’m sure it’s also possible to carefully lift the card off his desk during the very brief time that he steps up to the window, but you aren’t supposed to be in here. It’s a little risky to linger or throw coins. Also grab the security tape while we’re in here. You shouldn’t end up on CCTV, but there’s literally no reason to not grab it.
Use the keycard to open up both security doors and reach the lockdown ward where Agent Smith is being restrained. Only orderlies are allowed back here. You can get a uniform from one of two ordelies in a laundry/basement area before entering here,
but it’s ultimately unnecessary. Wait outside the office window for the standing orderly to go on patrol. Hop through the window and sneak up to the sitting orderly. Sedate him and dump the body in the container after stealing his clothes and cell key. If you forgot the key, then there’s another one on the table too.
Then just walk out and go down to the marked cell next to the pipe. Close the door and use the special action key to give him the poison. Note that it’s a long animation, so make sure that the patrolling orderly isn’t on the floor making rounds.
Once it’s over, just backtrack to the security office. You have three targets to hit and Smith will be handled by other people. We actually have to kill a little time anyway while they take him to the morgue.
Flatline - Dr. Death
This is actually an option for all three guys if you want. If you have a therapist uniform (we picked one up earlier in an empty office), you can walk up to each of the people. They’ll tell you that they’re ready for their appointment and walk up to the empty office. You can just sneak in after them and inject them with poison or strangle them.
Hide the body behind the table or sneak it out into another room. The single break room to the right should have a few niches too. If you just sedated them or knocked them out, then you could also drop them over the rail and make it look like an accident.
I personally don’t like this one though, since it’s a little tricky to plan and another therapist could walk into one of the rooms and see the bodies.
Flatline - Killing the Green Guy (Carmine Desalvo)
This guy is generally the trickiest to kill, since his accident is hard to pull off and his stash is tricky to access.
He mainly walks around the gym area to the left of the entrance. He takes short walks out to the garden pond, drinks from a bottle of alcohol he has by a cherub statue and then walks back. He has a guard with him for all of his time outside and the gym is fairly well secured.
Well, like the intel says, lifting weights is dangerous by yourself. Step behind him while he’s lifting weights and wait for him to wear out and put the bar back on the rack. You can hit “E” to drop the weights back onto him and strangle him. Note that you have to actually strangle him, which is something that the guards might notice. Make sure that you save first and try to keep an eye on the entrance to the gym and the break room off to the side. If the timing doesn’t work the first time, then you’ll have to wait and try it again.
You might also get lucky with a quick staged accident. He’ll stand in front of the mirror posing for a bit after he’s done with the weights. If the passing guard isn’t around, it shouldn’t be impossible to sedate him or knock him out and drag him into the spa off to the side. He should die if you dump him into the pools.
He may have a guard outside, but the guard doesn’t watch his liquor stash. Walk outside of the gym and down to the pond. His bottle is right next to one of the peeing statues. The only problem is that a nurse takes her breaks by the pond. Either wait for her to leave or knock her out and drag her back to a blindspot by the balcony or tree.
Inject the poison into the bottle and walk away. It will all take care of itself in a few minutes.
Flatline - Killing the Blue Guy (Lorenzo Lombardo)
This is actually pathetically easy. Walk into the other upper wing of the clinic. Not the therapist’s rooms but the private rooms. Room A is always empty. It will actually be your room if you enter the clinic as a patient. Walk inside and walk out to the balcony. He’s in room D, which is connected by the balcony. Just walk along it and enter his room through the balcony door. If he’s in there, wait for a few minutes. If he’s not in here, then you can just sabotage the gas on his makeshift stove. It will blow up the next time he uses it.
If you want, he also keeps a bottle of alcohol in the kitchen and occasionally walks into there, but the accident is so easy that I can imagine doing much else.
Flatline - Killing the Pink Guy (Rudy Menzana)
You have to work a bit for this accident. The accident and the poisoning are actually in the same place though. It all goes down in the library that he has turned into a private study.
Walk upstairs to the therapist area right next to the library. You should be able to walk into the little break room on the right and find the balcony that overlooks the library. The winch for the hanging chandelier is right here. Plant a bomb and wait for him to go in for a drink from his secret stash. Step in a stairwell when he starts the animation and then blow the charge to kill him in an accident.
Poisoning him is quite easy. Anyone besides a patient can just walk past the lone guard on duty while the mobster takes a walk around the facility with his guards. No one usually looks inside, so just save and then pop the globe open. Poison the bottle inside and just let nature take its course.
Flatline - Escape
Remember that we aren’t done just yet. We have to pickup Agent Smith at the morgue and escape with him. Go ahead and pick up your suit if you want. It’s not too hard to slip into the morgue unnoticed and it has no windows once you’re inside.
Walk down to the gate and look at the windowless building on the left. You should be able to just wait for the patrolling guard to face away from you and then pick the lock to slip in fairly unnoticed. We’re almost away anyway. Use the antidote on Agent Smith through the special command and walk right out the marked fire exit to escape from the level.