Hi, I’ve recently begun a playthrough running version 0.9.0-n. When I grabbed the keycard with my hook, I, of course, ended up flinging it into the void at the bottom of the stairs. It did not trigger the failsafe and respawn on the roof of the bunker. I have spent the past hour or so looking at previous issues with this bunker, and trying some of the various suggested fixes (clipping through the roof with ragdolling, clipping through the door with chairs, beating the door despite it’s invincibility, holding kerfur up to the door). I’m also not certain enough of my technical abilities to do shenanigans with the game version and save modifications. Does anyone know any reliable fixes I could try?

using the mailbox, send the card from another save to your current one.

You could download debug mod and spawn the keycard in, if you're not sure how, look up r2modman. It's pretty easy to use.

i personally just reloaded.  my last save was right before i even tried, so if yours was there then reload, and if you dont know, it never hurts to try