Who covers medical bills after a car accident on a commercial parking lot?

Bit of a weird story, but I parked my car at Walmart, got out of my car, and someone in the car accidentally took the car out of park. Car rolled back and went over my foot and ankle. Had to have surgery and spent a week in the hospital. Car was put back in park without any damage to the car.

Someone from Walmart’s insurance team has been trying to contact me but I haven’t talked with them yet due to being in the hospital. Walmart is not at fault in any way, they just happened to own the property where it happened.

Is this something covered by my accident/auto insurance, my health insurance, or does Walmart’s insurance cover it? I assume it comes down to particular plan details, but I’m not even sure who to talk to first.