Complete the game, any ending will suffice and it doesn't matter who survives (if anyone). Just complete it once and you'll unlock this trophy.
I'll give a brief description of what is needed, this may differ SLIGHTLY depending on who makes it to the final area.
Ethan will walk in to the warehouse, walk all the way to the back and when you gain control again, there will be a pipe to the right (I think there's also one to the left, not sure though), grab it and force the grate open (if only Jayden makes it, he will shoot the lock).
The killer will appear and say he's been looking for a father capable and allow you to rescue Shaun, but will pull a gun on Ethan. Jayden will come out of nowhere (seriously, the direction he comes from is just a wall) and tackle the killer.
Ethan will then need to perform CPR on Shaun, which is done by a various assortment of button presses.
Madison will arrive and inform Blake (the douche cop) that Ethan is innocent and she knows who the killer is, but will be arrested before she can say anything. Perform the needed QTEs and she'll break free and jump on her motorcycle, keep performing the QTEs and she'll run into the warehouse with Ethan.
Jayden will engage the killer on a conveyor belt, he can either die here (Jayden) or survive the fight, as well as the killer.
Once the killer dies or escapes, and the final cutscenes run, you'll earn this trophy.
---- The EASIEST Way----
Have no one survive the course of the game, have everyone die as soon as possible and you don't have to do anything. :D
Like I said, how this plays out can differ depending on who's there, if you have any questions, please post them and I'll answer them.