The players will not react in the same way, Kaychsea. The DM is there to be a referee, not to make the monsters and NPC's as brutal as possible. In games where characters die at 0 hp, the DM should divert some of the monsters' attacks to other PC's. The loss of a character, even the potential loss, is often a traumatic event.
DM's would also be good to not use area of effect damage when it could kill dying or badly injured PC's.
DM's would also be good to not use area of effect damage when it could kill dying or badly injured PC's.