So a few years ago I heard this story. I tend to think it is true.
A former boxer, pretty good boxer, he became a policeman after he had a good boxing career.
One night he was called to respond to a disturbance at a night club. Some kids were fighting so he had to break them up. Caught one, asked him to get in the car to drive him to the police station. The kid, teenager, cried and said something like this:
-Please mister, at least let me tie my shoelaces.
The policeman accepted... the kid went down, took a knife he had hidden in his shoes and sliced the policemans' throat. He was dead before he hit the ground.
Now this is to emphasize that anyone, no matter how well trained, how strong, how anything you want, can be killed by anyone else no matter how weak, how untrained, etc. As long as there is a way to do it.