I ran into a pretty annoying bug - I saved in the sewers in Chapter 3 and when I loaded I appear to be stuck on the wrong mapping layer. Which means that I keep running into invisible walls, and I can walk through some regular ones which just leads me into a place you're not supposed to get to - the white bloom stuff that's placed around every level.

So I can't get out of the sewers, and I only have two saves there that both have the same problem. Is there a save game editor or a teleport console command?

None that I am aware of.

Seems like your save is corrupted, so just return to an earlier save after rebooting.

You do make manual saves often?