If I knew he had a vest on I'm not sure, probably aim at the head and try for a CNS hit. If he was moving fast laterally the head would be a difficult target but it's still a lot easier target than a clay pigeon winging out there and I can certainly hit one of those.
Hard to say, really.
It would most likely be pitch dark so the first shot would be directed at center of mass since I wouldn't know he's wearing armor. But it's a good subject to think about. Maybe have to practice a variation of a Mozambique drill - one to center, one to the groin and one to the head - one of those should get him.
