Death is what happens when your hit points reach zero. It is not the same as collapsing: an empty vigour pool leaves you prone and recovering, while an empty hit point pool leaves a body.
Respawning
A character a player is driving comes back — where and with what is a rule the world itself sets, so one world can be forgiving about your belongings and another can not. The world's people are not so lucky: a resident who dies stays dead. Killing somebody in the world is a permanent fact about it.