Funnily enough, I was planning on making a Courier 0:00 TAS for April Fools' Day, but it didn't pan out. Here's what I found, though:
After unpausing, there is one frame where the timer doesn't update. In this frame, Bond's position will update, but you actually lose a bit of speed, all the way down to the minimum speed (in other words, zero EXCEPT for Cold Reception). So in most cases, you would eventually stop moving, so you would need to reaccelerate, which would cause the timer to update. You also can't perform any actions (shooting, opening doors, etc.) in the unpause frame. So basically, 0 seconds isn't possible on most levels.
However, in Cold Reception you have a nonzero minimum speed, which is why it works so well here. Assuming that you don't die, you could theoretically get as low as
13 frames of in-game time here (first pause at 11 frames and 1 frame to shoot each of the 2 fuel dumps).
Also, if you're not aware, I've been working on a TWINE TAS for some time now, and I'm about a level and a half from completing the whole thing. There's lots of information in the video descriptions, so surely you'll find something interesting.
https://www.youtube.com/channel/UCQBTYkrfJC4tX-FAc66125g/playlists?sort=dd&view=1&shelf_id=03) Does any video of the strategy exist? Any theorycraft or TAS? Or were Bcks’ destroyed VHS tapes the only recording ever? Why haven’t you or anyone else tried it/recorded an attempt, even if just for theory?
I have a TAS of a short segment of Courier (about 1 in-game second). If I knew of a way to record Bizhawk with lua outputs, I could make a comparison of pausing vs. normal play showing certain memory values.