If you wanted to die in aviation in World War II, there were few options better suited to make this happen than to volunteer to be a rear gunner on a dive bomber!
Essentially, in an attack, your body was a second layer of armour protection for the pilot! Of course, he had a back plate of armour and the gunner had nothing but air and wafer thin aluminum skin! The weapon most often fitted was a single or double 30 cal MG -- a weapon that had already been deemed woefully inadequate to shoot down a fighter aircraft, even when the British put eight of them on their fighters to shoot with! Now imagine you have just one (or at best two of them) and you have to manually aim while your pilot is violently maneuvering the aircraft if he has any hopes of living!
Oh, almost forgot, if the enemy fighter pilot has any options and plans his attack, he makes a slashing run from the side and above, or dips down below your belly and rips your bottom out beneath your feet and peels off and to the side before emerging above you.
One of my uncles was in the US Marines in WW II and was given the chance to volunteer to be a rear gunner on an SBD. He professionally declined and prayed no one asked him a second time!
Ken