I don't understand how a flashlight works (its bug or not )

Mikasa

how am I supposed to understand this where in the first video I blinded a maniac and nothing happened

https://youtu.be/8o1ni-xI6Y8

I wasn't blinded here

https://youtu.be/CQr1tUb1Aq0

and in this video, I was blinded, even though I had time to look down and away

https://youtu.be/FQhf0RT3gUE

I can't figure out how to use the flashlight properly. And most people don't know how to use it properly either

In training missions, there should be a video instruction on how to properly blind a maniac or something like that