Go on a server with many people on it and go in a city. Have 3 people. One observing, one being a test dumby, and one being the killer. I believe this only happens when the killer is desynced. Once he is desynced he can see old or even just unrelated positions of players. They can be somewhere where they are not actually at. He can then shoot at them or punch them to give them damage, even though the test dumby is still at a position where he is nowhere near the killer.