What would you have done?

You come across two people fighting at a train station.  They are wrestling on the ground.  One guy is on top of the other.

Suddenly the guy who is on top pulls a knife...

[Warning - disturbing footage following.]

The video below was posted on Facebook with the following comment:
I just saved dude life,i have blood all over me,i almost got stabbed in the neck,i missed my stop,came back to save somebody life,oooooomy god im shaking


Clearly the bystander then stopped his own video recording of the incident and went to the aid of the victim.

It seems the victim survived.  This separate footage taken from the train was also posted on Facebook, accompanied by the following comment:
Fools fighting at ashby trainstation...#901 rice street...smh


Would you have intervened sooner?  If so, how?

I'll leave you to comment, but please keep your comments restrained - not to mention respectful towards the bystander who, whichever way you look at it, put himself at risk and rescued the victim.

Bear in mind that what we would all like to think we'd do is probably different to what we'd actually do.

Copyright © 2014 Dejan Djurdjevic