I've got some experience with very fast , close encounter shoots in constricted areas shooting black bears.
One shot was all I was able to get off, .
Several were in very tight brush, with the firearm at the ready, one was in very low light conditions, and one was when I was inside a cabin -yes, inside!
The actions used were a bolt ( .303 Enfield) pump ( 12gM37 Ithaca),
and single shot ( break action 30/30, .500 Hawken, and .58 Hawken)
All the bears were killed with one shot , and there would have been absolutely NO TIME for a second shot, with any type of firearm.
I really think the type of action is secondary to the initial accuracy of the firstt shot, but that is just an opinion....
Cat