You just found a bug, I guess I'll have to make another version. :)
To not make you have to start the game again, here's a workaround:
Here is described how to activate the console:
http://steamcommunity.com/app/251730/di ... =german#p2
(try it first with the standard key in the config-file before changing the number value)
Open it with the ^ key (after restarting the game after the above changes).
Then type in:
air_elemental_2.monster:die()
air_elemental_3.monster:die()
That will kill both elementals.
Joerg