David's Test of Testoterone

I’ve only known David for 18 years. Therefore, I can’t say the following incident is the most foolish thing he’s ever done, but I think I can pretty safely say it’s in the top 3.
Mistake #1: Entered a confined space (subway) with a big hostile man.
Mistake #2: Maintained eye contact with said man who was cursing and shoving.
Mistake #3: After being pushed, put aforementioned man in a head lock.
Mistake #4: After persuasion from man’s girlfriend, released man, who was raging mad, from a head lock.
Mistake #5 After being approached again, placed man under head lock #2.
Mistake #6: Released man who was raging mad, and whose girlfriend fainted, from head lock.
Mistake #7 After the man chose to ignore girlfriend’s state, placed man in head lock #3.
Mistake #8: Released man who was raging mad from a head lock and exited the train.
Mistake #9: Assumed man would remain on the train to attend to his ailing girlfriend.
Mistake #10 Turned his back on the man who also exited. David received a blow to the head. David karate kicked at the man. The man, hoping to avoid additional confrontation, ran backward into a pole as David verbally belittled him.
Smart move #1: David speedily departed amongst shouts of “Call the police.”

Scary: He later found out that a few days before a man had been stabbed on the train.
Smart move #2: Filed a police report and will use a different train for a while.