Seth (Station 19)

Seth is the on-again, off-again boyfriend of JJ.

History
Seth was at JJ's house and they were trying to have sex, but they were interrupted by the smoke detector in her house, which kept beeping. JJ said she'd changed the battery the day before, but it wouldn't stop beeping. To get it to stop, Seth took a baseball bat and hit it, breaking it, but stopping the beeping.

Romantic
He is romantically involved with JJ. She describes him as her sometimes-boyfriend.