Yeah I transferred, and also for family reasons (however, I did need to transfer to a "lesser" school in order to be closer to home). Haven't had med interviews but for all of my research/medical job interviews thus far, I just said for family reasons, and it wasn't an issue after that. Transferring is more common than you'd expect, and people transfer even if they don't "like" the school. It's not a big deal, and certainly not something I'd panic about.