Trigger Happy

You're a thief who broke into a museum of bizarre artifacts in hopes of finding something worth selling. One of the objects you found looked like a pistol of some sort. The moment you grabbed the gun to inspect it closer you could feel it start vibrating slightly before it started shaking strongly. Then it fired suddenly a bullet and went back to slight vibration. You tried to drop it but the gun didn't fall onto the floor, instead it was hovering in the air right in front of you. You didn't have time to ponder on it for long because you could feel it shaking again and then it fired another bullet. No matter what you did the gun didn't stop firing after a short delay nor did it stop being in front of you, so you decided to get out of the museum. There was however one slight problem, how were you gonna be a able to sneak out with a gun going off every now and then considering breaking any other artifacts in the museum was surely gonna set off the alarms. Well only one way to find out.