You get the 2 XP the moment you search outside, so you can spend that and any other XP you might already have before or even while rolling to defend against the card. What I mean with the latter is, if you draw a thing attack and you have 3 stamina, you could roll to defend against the attack and if you end up 1 success short, you then could still spend any XP (incl. the 2 XP you just got for searching) to unlock the Cardio, to get back to 4 stamina for example. That means you now have 2 natural dice and you can roll that additional die and add it to your previous roll to defend.

Long story short: You gain 2 XP the moment you search a phase deck, before resolving the card and are free to use it immediately.

And in general, you can spend XP and play cards at any point in your turn. You can do that before you resolve any event during your turn, after or while resolving like after the roll to defend to alter the result, add dice to the roll or just get rid of 1 of the 2 strikes you might have before getting a 3rd strike for missing the roll). You can't spend actions and can't move while resolving any event though (means the moment you flip a phase deck card or roll against the Camp event).

Does that make sense? :)


(I always take advantage of that and hold back playing cards and/or spending XP to alter my roll and such until I know I need it)