A: There are tons of Actions which involve taking multiple steps to complete them – for example, Actions which involve the redistribution of -eepers (Keepers and/or Creepers). One might wonder whether someone could win as soon as they get one that completes the current Goal, or whether they must wait for all of the cards to be distributed.
In general, Actions (and Free Actions) should be treated as though all of their steps occur simultaneously. What this looks like is executing it in its entirety before checking win conditions. It’s as though you stopped game-time and created a little bubble in which you do all the things required, then turn game-time back on again. Imagine the game blinked, and when its eyes open,
The exception to this is cards which create “subroutines” which invoke the utilization of other cards, where each card played is considered separately, and one might win because of one of those cards before all cards in the subroutine are addressed. Most of these just happen to be prefaced by “Set your hand aside,” though that aspect isn’t directly related to this ruling. It’s just that utilizing other cards as a separate subroutine usually means keeping them separate from the rest of your hand.
For a list of cards which create subroutines where other cards are executed separately, see: If I am executing a multi-step Action (or Free Action) which involves the playing of a bunch of other cards, can I stop as soon as I win, or do I have to play all of the cards?