No need to bust the Glass. When I locked Keys inside of the Car the Auto Club came out and used a plastic wedge to pry the Door out a little. They then inserted something like a Blood Pressure between the Door and Frame and squeezed the Bulb and inflated the That Thing untill there was enough room to stick their Wire Tool in and pull the Door latch Lock.
Note: that was not on a Mercedes.

The Tow Truck Driver sent by AAA opened the Car.

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84 300D, 82 Volvo 244Gl Diesel