Seized Pedal?

About an hour into a two-minute pedal swap I came to the realization that I had a seized pedal axle.  The 8mm allen head on the pedal axle was stripped, my vice grips wouldn’t  grab the axle, and I was running out of options.  I tried penetrating oil, heat and large blunt objects.  Nothing was working.

As a last resort I put the crank arm, pedal axle and attached vice grips in the freezer and went to bed.  The next morning the axle came right out.  I would not have guessed that freezing a steel axle in an aluminum crank arm would have helped, and it may not have, but in any case the axle is out.