A while ago I discovered a way to reach the 2nd Outer Atlantis exit on the 1st visit, sadly there seems to be no way to make the game actually let you progress further, so I guess I'm only posting this to spare the time of anyone else who might try looking for something.
More info (including a clip of how it's done) can be found on our Discord server over here: https://discord.com/channels/730768870947684442/730771405746208819/885356063782735922
At first I was thinking of posting this to Guides, though considering it's useless at it's current state, and not even a proper guide to begin with, I decided to just post it on here as a thread, for anyone who might have missed it on the Discord. (or is not even there)
Anyway, I'd be more than happy if others tried messing with it and let me know their findings, though I'm fairly certain I have already tried nearly everything there is to be tried, all to no avail, so I'm not really getting my hopes up for this to get anywhere...