The two handles on the wire is probably the best bet.
Some have used guitar wire or piano wire but the principle is the same. Feed one end through and saw it around the glass.
I would also suggest having a friend to help.

That being said I usually do these things myself and bought this guy. It has a 90* bend in the blade and cuts the seal from the out side of the car. Works very well.
I have broken many windows before I got this tool. Not one since, well except for the one that fell out before I had a good grip on it. Another good reason to have help.