The thing is, with that example you have given, the muzzle flash is being reflected because a) it is close to the trooper and b) it is reflecting off its surroundings because the walls and partly open door is reflecting it. If a flash is captured on camera, doesn't matter if it is 24fps or 124fps, the reflection would also be captured.
Just because the troopers in the PT get lit up like Blackpool illuminations whenever they fire a shot does not mean that this is what you would see in real life. You can even see in that example that there is no flash reflection in any of their visors. There are so many factors as to why there wouldn't be a reflection. One being that the gun can actually block out the brightest part of the flash. Studio lighting/ bright lighting is another.
As i said, it's not something i'm going to be bothering doing.