I would be really worried. It happened to me once when I was a late appointment and left the building after it was locked, and someone went in as I exited. I worried that my therapist was alone inside, but I also worried about making too much of it, so I did not email. Nothing came of it, but if I had emailed and did not hear back, I would have been scouring the police bulletin for reports. I have been a crime victim and this sort of thing puts my imagination in overdrive. I hope you hear from her soon.