Unfortunately, sadly unbeknown to her 6 months ago he asked someone to stop and they didn't, which very nearly killed him. When he asked this person to stop and she didn't, experience told him his life was in danger and asking people nicely who don't obey can kill you.
If you nearly get killed, next time you're in that situation instinct and training tells you to act.
Very sad, hindsight is a wonderful thing.
As @Squaredy says, whatever country you're in, just do what an armed under pressure cop tells you, whether you agree with it or not. Its the person without the gun who unfortunately is the loser.
Like when a pedal bike carves up a lorry on a busy junction. If there's a collision, whoever is in the right or wrong, the bike is always the loser and there's no round 2.