When the Mentor Aspect is the target of Unlock the Gates of Deepest Power, what happens?

When the Mentor Aspect is the target of Unlock the Gates of Deepest Power, what happens?

Shifting Memory of Ages draws two Major Powers, gains them both, and forgets nothing. If they meet the threshold requirements, they can play one of the new Power Cards – since the identity of "the Major Power" is ambiguous, Shifting Memory of Ages chooses which one is being referred to.
It doesn't matter who played the Power, just that Shifting Memory of Ages with the Mentor Aspect is the target.