Strika I do agree with you, taking the life of another no matter the reason is not right. But not nowing the circumstances of what this person has done it is hard to know the reason or even the exact nature of how they "rammed" him off the bike, I would suggest they didn't run him over so perhaps it was just a bump to knock him over.
As I say though if you do the runner and are then relying on the good nature of people then you may want to look at the human race generally and how we have evolved, people's behaviour changes when anger and andrenalin are pumping through the veins, thus you are now taking a risk.
Nick