If you enter a garage that is connected to a house or building without having to go outside, then you may call Shotgun as soon as you enter the garage, if the vehicle is in the garage. This only applies to small attached garages.
2.8.1 Parking structures and detached garages, even small ones, are always considered to be outdoors, even if they are underground and connected to the building, therefore they fall under the Line of Sight rule.
2.8.2 If you have parked your vehicle with a Valet, Shotgun is called when the deed is done and you have left the venue, even if the Valet has parked your vehicle in a parking structure.