Apologies. So many people still can't figure out how to find the giant gaping hole in the wall after they blow up the assembly line that I rarely bother to read anymore. That response solves their problem 99% of the time (down 100% thanks to you and your "Special" issue

)
Anyway, if you've completed the section and you're on
PC, and for some reason you're just stuck in the room without reason, press the tilde key ( ~ ), click on the offending door, and type "Unlock". Press Enter, then tilde again. The game once locked me in
and I had to use that command to get the door to open.