There are a lot of cards where, unless all steps are considered to be simultaneous, there could be timing issues.
A: A good rule of thumb is that most things resulting from a single card play in Fluxx (and many other Looney Labs games) are considered to happen simultaneously, so if there are timing issues, assume that things take place all at once, and then consider the outcome. There are a exceptions to this, but you’ll notice they follow a pattern: Draw 3 Play 2 of Them, and Draw 2 and Use Em result in actual secondary card plays, and you could win after one of those sub-plays, and Take Another Turn, since that’s a delayed thing that also results in secondary card plays (your entire second turn).
But for things like exchanging, or redistributing Keepers or Creepers, those are considered to happen all in one instant. As stated before, if you’re bumping into an issue which could go one way if it’s simultaneous, or another way if it’s not, it should almost certainly simultaneous.
See also: We think we broke the game…