... who exactly stabbed to death Fuller. At the end of the said chapter Darren gave a synopsis on how the things had gone on. At the time my father interrupted me to say something irrelevant and I let slip the ending of Darren's monologue past my ears. Will someone give me a little sum-up?

So far from what I've seen it does point to that but slightly different.
(Watched the outro video out of curiosity, didn't really spoil anything as such and as said in several reviews it's a bit rushed and set up for yet another sequel.)

You need the three plastic bottles from that room, developer fluid, fixing fluid and distilled water, one of the basins need two of the contents to provide a mix and the other only needs distilled water, the machine itself needs the film roll and the fixing fluid and you need to have acquired the photo papers from the tourist bureau or what to call the place, it's one of the timed puzzles as well but nothing difficult, five seconds or so for the enlarger to function in terms of brightness and a bit longer for the developer batch to fix the contrast, needs to be done twice and then it's automated and the puzzle is solved and you'll get all 36 photos without having to develop them individually, thankfully.

The tray on the left needs to be filled with half developer fluid and half distilled water, the one in the center with pure distilled water.
Once you've done that, put the film in the container and pour the rest of the developing fluid in the container. Then pick it up and use the fixer on it to stop the development process.

get fuller out of the photostore so I can steal the film and so on. i've talked to the blonde and she want's some examples, and i haven't found a way to get any samples!

Magazines lying in the waiting area of the hospital