I see, sacrifice by common men/women, without any special training, against certain death for a non personal cause is one of the unifying positive trait of humanity across time/space.
You could argue that the average suicide bomber expects a personal reward in the afterlife.
You could also argue that altruism isn't real, and doing altruistic acts is rewarding for the individual, but that seems a little reductionist.
I could, but altruism is too fantastic to bother.
the "non personal cause" could be tricky though, I see that for example with religious people doing things for non personal causes- they are actually gaining from it but not money or fame, could be "points" in the afterlife or happiness