> I’d bet chopper strobe flash reflection or a camera lens aberration from the chopper.
Stepping frame by frame that does not seem likely.
Looks like the agent on the left (in short sleeves no less) hit him with some kind of incapacitating device. I don’t think it’s a taser, at least not one of those shaped like a pistol. The agent also ducks his head at the same time - not sure if that’s a response to the other agent’s gunfire, or some reaction to the device he was using. Another thing, the agent looks down at the device after its use. That’s not something one would likely do if it was a familiar sidearm.