The world would be a safer place if people didn't do dangerous things.
Action sequences are generally split into 12 second combat rounds. That's five combat rounds in a minute. This means that in the inestimable "side scroller" fight in Old Boy, that the fight goes on for 3 rounds before Dae-su Oh spends a round pretending to be unconscious before he goes at it again. The fight between Spiderman and Green Goblin goes:
- Round 1: Green Goblin throws Peter through a wall
- Round 2: Green Goblin throws a bomb through the hole in the wall
- Round 3: Green Goblin taunts Peter
- Round 4: Green Goblin and Peter exchange punches
Considering how many dice get rolled, such flurries of action can already take a fair amount of time to resolve, so breaking the time down finer than that is generally not worth doing. In fact, when the action gets to even slower parts like cross city chases and boat maneuvers, we pull out of combat time altogether.
Remember that while it is theoretically possible to let loose astounding numbers of bullets in just a second or two, in actual combats it's entirely likely that any particular 12 seconds will go by with no shots at all. Fog of war takes quite a while to roll out.
Normally a character may take one Complex Action or two Simple Actions during their turn. A character may do some relatively large number of Free Actions, and like Complex and Simple Actions, all of these are done during the character's turn. Reactions and Movement are done while it is not a character's turn. Interruptions are rare in After Sundown, and normally an action is fully resolved before the next action is declared.
"Then I attack, then you attack twice, then I attack, then you attack once?"
At the beginning of a Combat Round, every player rolls Intuition + Agility. The number of hits is their Initiative Score. Characters act in order of Initiative Scores, and characters whose scores are the same act simultaneously. A character who gets a higher Initiative Score may choose to act after characters with a lower Initiative Score if they want. Each character gets one turn. Characters who are entitled to extra Initiative Passes (either because they have activated Celerity or because they bought them with Edge) get an additional turn after everyone else has moved. The most number of turns you can have in a round is 4.