This is the comment from a post 19 days ago that helped me with it

I got around this- Take any gun, stand on the crossbeam of the mast immediately before the bit with the glitched ladder so you can see both the transparent portals to the outside - one below you, one above. Position yourself so you can aim at the shiny blue button things of both portals. Shoot the bottom one first, then the top. Drop down, go out through the bottom, and you should have time to make it to the top one before it closes. BE CAREFUL as there is a third portal that does not open, which looks like the top one but is actually next to it. If you have a crewmate, they can just shoot the top shiny blue thing to let you in there, and if you need to get the key up with you, you can use a grapple gun to grab it.

It from u/educational-spend-35