Mess with her

You use your mental powers to prevent her from seeing you as she steps off the stairs.
"Is anyone here?" She shouts, to no response. Now confident she's alone she approaches the weapons cases. You walk up behind her and spank her leather clad ass with your hand. She spins around with a fist, which you just manage to dodge. You stand right in front of her, knowing she can't see you. She looks confused. "Hello!?" No response. She seems to convince herself she was imagining it then turns back around. The weapons she's looking for appear to be in a drawer at the bottom of the cabinet, so she bends over in front of you, sticking her ass in the air. How could you resist?