The end of the hallway was pretty far, but eventually you reach the end. You had to cut through quite a few enemies on the way but the battles were so uninteresting and easy you skip past all of them.

PETRE followed you the entire way because he was feeling lonely. Didn't help out much with the battles but kept you all company nonetheless.

At the end of the hallway is 1 (ONE) UNLOCKED DOOR, the other side seems to be very dark.