Infinity War League - "A Matter of Time" Crisis card

[RJ1040]

The card says

"At the start of a character activation, if it is holding a Time Fragment roll 1 die. If the result is Crit, Wild, or Hit they may make an additional action this turn. Otherwise, they gain the Stagger special condition."

When activating a character can you resolve this effect from the Crisis card first and then use Thor's leadership - Prince of Asgard - to spend 1 power and remove the Stagger you may have gotten from the Time Fragment?

[Negoldar]

You cannot. Thor’s Leadership activates at the beginning of the turn, before selecting a character to activate.