Hi I had two bugs towards the end:
- When Gary flees to the Janitor Closet and the lamp doesn't work I first tried going out the left hole and climbing up the vent again. Mark hopped on the wall, but even after pressing Spacebar pretty rapidly he couldn't climb this time. There wasn't a button to get off the wall, Mark was stuck, so I loaded the autosave.
- I did not arrest Gary, I left him where he was. In the part past the credits I went to the Janitor Closet and hmmmm Gary was still there. ;) I was able to arrest him at this point and proceed ok.