There are worse things than having someone point a gun at you, especially when the someone is pretty and the gun is fake.
She handles it just plausibly enough that you're willing to play along; you play along just enthusiastically enough for the feelings to kick in. The sharpness, the adrenaline, the same indefinable brightening that (in the field, when the stakes are genuine) you dare not call a thrill.
Poor, bored Mandy: she actually does know what she's missing. She might even know she's giving it to you right now.
There must be a way to return the favor.