Definitely a tough one, but you actually only have to kill one guy (the one actively patrolling the cell hall) and you can do it with traps to avoid setting off an alarm.
It requires a bit of luck, save-scumming, and some decent stealth, but it is possible, Basically, if you deal with the guy in the hall (using traps and patience hiding in the middle cell entrance), open the cell, and then block Timmy to force him to step out of the cell and into the hall (body block him so his AI has fewer directions to step in). You can get him halfway down the hall and then tell him to follow you out, at which point you can sprint/sneak past the remaining enemies by throwing stones (he will teleport out with you if you make it to the exit because the maps are so small).
The most irritating step is the rng of him stepping into the hall since there is one step that can set off the guys in the jerk-off session in the room across from the cell. For that step, Timmy himself wont set the guard off, but you obviously will, so you do have to save at that point and reload until he meanders in the right direction (into the hallway entrance). At that point, you can throw a stone and then move in to block him to make him walk further into the hall.
In a tough world like this, the players ability to manipulate the timeline is a necessary one to ensure good outcomes.
