Weapon lights are a neat sbuject. Some consider them bullet magnets. Others say you can't shoot what you can't see. I have tried in training to bump the light and move. Trouble is you are doing this in the dark or you wouldn't need a light (duh). When you hit that high output flashlight, guess what, you just destroyed your own night vision. If you lit up the BG, not problem, leave the light on and shoot. If not, you say you are going to shut the light off and dash away to put distance between yourself and where the light just was. Trouble is now you can't see. And in a gunfight, you are talking about a lot of stuff to be thinking about. Try this at home with an unloaded gun. Better yet, try it somewhere where you don't know the layout of the area. Be pretty stupid if you were so tactical that when you dashed away from the lit spot you ran into a door and knocked yourself out and the BG came over and stopped laughing long enough to shoot you with your own tactical gun.
IMHO (and some big name guys I have trained with plus some SWAT members I have trained with), entry teams need a light. Turn it on and leave it on. A dynamic entry is just that, dynamic. You are moving fast in the dark and you will need to see where you are going. You aren't sneaking and peeking, you are charging. And entry teams point guns at people all the time without shooting them.
I don't know of a single case where a non LEO used a weapon mounted light in a self defense shooting or a hand held one for that matter. Does anyone else?