(These theories are all based on theories from Episode 4 and some scene leaks of Episode 5)
Could we meet Rachel in Episode 5?
This is a possibility. In the scene leaks we see a lot of "Focus" scenes, (Jumping through pictures). Max might be able to jump back to a time where Rachel was alive and meet her, and stop her from going to the Vortex Club Party that she was drugged at and eventually killed.
Is there a possibility that there are more then one endings?
Yes, there is a possibility. In fact, there are two endings. If you killed Kate or not that will affect the ending. And, the person you blame in Episode 2 will affect the ending aswell.
Could Nathan get Max out?
Nathan can get Max out, because Nathan (MIGHT) have a crush on Max. This is based on Nathan having one of Max's pictures beside his bed in his dorm room.
These are all my Episode 5 theories for now. When Episode 5 realeses, I'll make another chapter. If you know any theories or want to correct me on some; kik me @thebatteries.