Oddly enough I’ve been in this scenario but on the other end, and my ex didn’t do what you’re thinking.

She had allegedly been unhappy for a few months (later found out she’d been dating her coworker that I had said I was uncomfortable with her spending so much time with, but that’s an entirely different story), and waited until 2 weeks before finals of my last semester of undergrad. We had been together 2 and a half years and living together for 1 and a half.

I came home from a presentation for my senior design project to find the apartment cleared of her shit. She came back to get the last of her stuff and I asked how she could do that to me during the most stressful time of my life, and she tried to turn it on me by saying I should be thankful she stuck around for as long as she did.

Bombed a couple finals from the stress-heartbreak combo and had to graduate after a summer semester.

I would wait, but not for the lease to end. Let her finish her exams and then sit down and talk with her. You can figure out the details of the lease issue after that.