M12 Tram Trust
Thanks for posting this! I have found it possible to get back in bounds by going into the vents from M7. But this definitely should be explored more.
Not sure yet how this is useful.
You can walk around quite a bit above M7, including the entire length of the vent duct at the start of the mission, as well as over the burning room. I wasn't able to clip back in-bounds from the ceiling (either by calling the elevator or activating the vent prompt).
It's possible to fall back in-bounds in the back of the vent where all the wires/cables come out, but you end up trapped back there and have to reload.
Recent runs
Level: IL - M4
Level: IL - M12
Level: DLC - Loose Ends