Ghost her.

Enough of this. You pull the cord on the electric razor. You weren't quite done, but if she's not going to leave you in peace, you'll just have to leave.
"Excuse me." You push past her, pulling free of her grasp in a none too gentle way. You head out of the bathroom and upstairs, not bothering to look behind to see what, if any, reaction she has had. Perhaps it's time for you to have a sit down with Jenna and Tara, all three of you, and discuss her behavior.
When you push open the door to your bedroom, you hear the shower running, still. Jenna's still in there. You can see her fuzzy outline through the smoked glass of the shower door.