I think it's more dark humor / coping with death than a plan. if that were someone's serious plan, they would probably consider killing themselves if the bomb didn't do it for them.
Correct. Even if I survived the immediate blast effects, I think I would be in for a painful and unavoidable death from nuclear poisoning. I don't have a fallout shelter. The best I could do is close all my windows, but those would be shattered I'm sure. And seeing as I live in a 5-over-1, I think my building wouldn't survive anyway. The [normally reasonable] fire safety of these primarily-wood buildings depends on a functioning sprinkler system, which assumes municipal water still works. That won't be the case in a nuclear war.
The only realistic plan for this scenario is to leave before the war even starts.
The only realistic plan for this scenario is to leave before the war even starts.