It's a water droplet on the plastic globe that covers the cameras on top of the vehicle.

I shot whites 0.579 seconds and blacks .624 seconds... for both it was nearly .1 seconds more to holster. But I think that's due to being right handed, and the z being on the left. I agree with earlier comments that it had more to do with contrast of what was surrounding the object/gun.

Donald, (aka the blue fairy duck) Please take me out of my animatronic hell, and make me a real boy!