Worms don't have lungs, so the possibility of it "drowning" is slim to none; it can likely survive for several weeks or until your turtle eats it.
cause I put a worm in my turtles tank case my dad said they'll attack it, & after like two hours it was sill moving. then it got eaten. LOL.
why do you ask? its not like they are meant to live under water jst like us lol
until it stops moving is my best advice lol