Have been playing this mod for a week or so now, and im at explore the vents, with a sidejob of return some crates to bill. Ive already gone and unlocked the security room, but i cant seem to trigger the next bit of mission, or find my way through. Using a TON of blocks dropped, im pretty sure i went through every line in that maze, but i cant find an exit that leads somewhere i havent been. There is a second piping first floor door, which seems to use the same key i had previously, but i dont have a second copy of the key. Any tips? Am i blind and missing a vent somewhere?