What drives people to rescue others?

Altruism is a trait that is often detrimental to the individual. However, human beings are a social species- in times past, we could not really expect to survive individually. Altruistic behaviors probably came about as a result of that. One individual (the altruist) might be maimed or injured in the act of saving another (or many others) and as a result, the group could continue even if the individual did not.

I can't say I know for sure, but I suspect that if it has anything to do with genetics, then it must be a reccessive trait. If altruistic tendencies are linked to a reccessive gene, then the gene(s) could be passed to future generations, whereas if the behavior were linked with a dominant gene(s), then it would have been a short-lived trait (ie, altruistic individuals would take themselves out of the genepool rather quickly).

An urge to save others!

"Humans are self-interested creatures..." that's a lie actually, it's psychology to rationalize being egotistical.

So it's a made-up truth.

Naturally humans are a group-creature, defending their weak, and old, providing for the Unit.

I'm amazed how widely carried the 'Humans are self-interested' lie carries though, because it's often put forward as a scientific truth, which is really, really isn't.

It's simply the Fight, or Flight response, the strong will wanna fight under pressure, the weak wanna flight.

Maybe because they don't want others to die. Would you save a kid from drowning?

They see the world as a ticking timebomb, ready to explode if nobody stops them. Good and caring people stand up for those in need, putting their lives on the line just to provide justice to a small place on earth while it makes such a small difference, but it is a difference, a change. These people see the world and are proud and valiant to stand up for it.

Probably a sense of moral and civic duty and, in the case of suicide, the denial of an individual's rights.