No way I'd reholster blind after a serious incident. Every time I've been in a really hairy situation the adrenaline dump has affected my motor skills enough that I wouldn't take it for granted that I could do something as "simple" as holstering my firearm.
Does that mean I take my eyes off my surroundings? I guess - or maybe I move to a safer place - I don't know. But I will not reholster without paying some attention to what I'm doing.
The stuff you can do on "automatic" becomes a lot less automatic in a high stress situation.