If you're really in a jam, you're aiming for center of mass and that's all. Whether the person lives or dies depends mostly on your accuracy, the caliber, and the exact path of the bullet.
It's also a really dumb idea to shoot into the air. "It fell to earth I know not where . . . " perhaps into the body of some innocent.
Bullets shot up into the air slow and stop usually if straight up, and they reach terminal velocity, and that is not enough to penetrate and kill people. Bruise the hell out of them yes, kill them no.
A bullet fired on a slight less than vertical trajectory will still slow and fall at something considerable less than the speed it left the muzzle. Those bullets can kill if the unintended target is close enough.
Either way though, you’re right. Firing into the center of mass is always a better option that shooting in to the air
>>Valdez then fired at least two shots in the air from his own handgun<<
“When the rockets go up; who cares where they come down; it’s not my problem, says Werner von Braun” (Tom Lehrer)
The Miami-Dade county police dispatchers routinely issue a “take cover” advisory 5 minutes before the hour on New Year’s eve. Ain’t multiculturalism wonderful?