There are many possibilities at the warehouse, depending on who is still alive and who figured out where Shaun is being held. In this chapter, everyone can die or everyone can live, or there can be a mix. Sometimes the killer will die, and sometimes he will get away with everything.
If anyone makes it to the warehouse, Shaun will be saved. Ethan or Madison will have to break open the lock with the white metal bar on the ground close by, or Jayden will just shoot it open. Once it's unlocked, tap repeatedly until you can tug the controller up to lift the grate on top of the hole. Reach down and grab Shaun with , then tap to pull him up. When you get him out of the water, you'll need to perform on him to revive him. Hold + then tug the controller down three times to perform chest compressions, and then hold + to perform artificial respiration. Do both actions one more time, and the boy will wake up.
Fighting the killer
Ethan, Madison or Jayden can defeat the killer, depending on who shows up at the warehouse. If Ethan comes to the warehouse alone, he'll have the option to shoot the killer or let him go. If Madison or Jayden fight him, it will be a long quicktime sequence, above the roof of the warehouse. In that case, you will die if you fail the sequence. In certain scenarios, if you do well enough at the quicktime sequence, the killer will fall off the side of the platform and barely catch himself. You'll have the opportunity to help him or just end the fight by letting him fall. If you help him up, he'll attack again and you'll have a few more quicktime actions to finish him off.
Someone shows up
When everyone makes it to the warehouse, Ethan will save his son, Jayden will fight the killer, and Madison will have the opportunity to make it inside and warn Ethan about the snipers outside the warehouse. The only difference from the two sections above is Madison's part, as it requires a quicktime sequence to get into the warehouse.
If Madison or Jayden come to the warehouse alone, they'll have a quicktime fight with the killer after they rescue Shaun. If Ethan shows up with either Madison or Jayden, he'll save Shaun and the other character fights the killer. If the other person is Jayden, then Ethan will be shot when he leaves the warehouse. If the other person is Madison, the cops don't show up, Madison doesn't have to do a quicktime sequence to get into the warehouse, and they both survive.
The other option is that Madison and Jayden make it to the warehouse but Ethan doesn't. In that case, Madison will fight the killer and Jayden will rescue Shaun.
No one shows up
If no one is there to save Shaun, he drowns to death and the killer wins. The police may still learn the true identity of the killer if Madison didn't die in The Doc, but he'll escape unless Lauren is still alive.
If no one shows up at the warehouse, it's because they're all dead or locked up. Madison and Jayden both have two chapters each where they can die, and Ethan won't make it if he was arrested twice. Not figuring out the location will also keep a character from making it. Madison won't learn the location if she doesn't put the correct password into the laptop at the killer's place, Jayden won't learn the location if he gives up in ARI or doesn't have enough clues, and Ethan won't figure it out if he doesn't complete enough trials or he picks the wrong location on the GPS.