There are a number of cards which refer to "gaining" an ability.
For example, in Skirmish, Fenn's Trooper Assault, reads "After a friendly TROOPER within 3 spaces resolves an attack, it may gain 'Assault'. Limit once per round."
The "Strike and Subdue" Agenda card reads:
"Keep this card secret. Play it during any mission during a figure's activation. That figure gains:
<Action>: Choose an adjacent hero who has suffered 2 or more <strain>.... (snip)."
When abilities are "gained" in such a manner, are we to assume that the figure only has that ability for its current activation, and then loses it afterwards?