You're far too late. What a stupid move. Almost as soon as you start running towards the gun, Mary Lynn sees exactly what you're doing and reaches for it herself. Like a bolt of lightning, you see a giant arm strike in front of you, seizing the gun and pulling it away just as quickly.
You turn to look and see the giant Mary Lynn has a look of fire in her eyes. You know you're in big trouble now.
Mary Lynn keeps an eye on you as she examines the gun, not that you're going anywhere, standing on a random shelf in the college library. After a few moments, she pulls a book out of the stacks, places it on a shelf across from you, carefully points the gun at it, and fires. As you both expect, the book shrinks to a tiny size. She then changes the setting to "grow," points carefully again, and restores the book's size.
"I'm impressed, you little shit," she says, turning the gun over in her hands. "I can see why you wanted to use it."
"But I'm not going to fuck it up." A chill runs down your spine.