Leave.

I think a lot of people are mistaken calling Rapture 50s-esque the way Fallout clearly is just because it takes place in 1959 and 1968/looks vaguely "old-timey". The construction of Rapture started in the late 40s, and, as soon as people went under, they never had contact with the surface culture again. Not only the American post-war economic growth evaded them, they didn't have any references to clothes, music, literature, cinema, *anything* from the 50s. Also, I think, Andrew Ryan being an immigrant ties into this neatly. He arrived to the US right before/at the start of the roaring twenties, witnessing the opulence and monumentalism and hopefulness—after persecution and starvation and being on the run as a small child. His youth coincided with the boom of the post-WW1 decadence of the US, of course he'd like to capture that feel and style forever, leaning more on the 20s and 30s than the 40s. If anything, the 40s are barely represented in Rapture, as if Ryan wanted to erase everything possibly related to WW2, it's very Metropolis-like. Rapture is a literal tin can of Ryan's dreams and memories which exists outside the surface world timeline.