RPGMemes

Damage dealing cantrips are pretty much guaranteed to one shot commoners and have a decent chance on low HP enemies.

Create water would have a lower chance if it was created in their lungs since they could cough it out, and at best get disadvantage for a round. Unless they were in a limited space where they couldn't get their head out, then it would drown them like putting flammable substances on them and then throwing a Fire Blast.

All that said, I wouldn't allow them to make water in the lungs because it doesn't fit the theme of the spell any more than being able to cast Create Flame inside the lungs.