There are three car gates in the garage entrance. The one on the left (from inside) is the guest entrance (I think it's visible in the photo of Prisma's car), so theoretically a-non resident could drive into the garage if they had the entry code. This seems possible. If she did get into someone's car right there, how do you explain her making another 8 calls in the next 10 minutes? Some of them supposedly to the same person that she just got in the car with.