I may have found a hard lock point in the game where it is impossible to continue, when getting out of the vents for the first time and saving the girls from the Freezer, if you exit the vents to the North and you are in the room with the Hobo in the cardboard box if you talk to him then pan the camera back towards the door to get out, the door in this room disappears and is replaced with handprints.
I am assuming that this room is not meant to be accessed at this stage in the game, as I am missing an item needed to get out of the room if the door disappears.
I waited in this room for 10 minutes and used the Scanner / Mirror and tried to see if I was missing something obvious, but I could not get out, and had to reload an earlier save.
I am playing on the latest Version 0.16B
Great game btw and I am loving it so far.