We left a pepsi can (sealed, unopened) in the freezer and next thing we know, (quite a few hours later) it's expanded, like the top is all popped up and the bottom is too. So now it's sitting in the fridge, most likely already thawed.. if I try opening it, will it explode? Should I go outside? Or is it the other way around, has it lost its fiz? Help!

Should be fine, but, yes, open it outside.

Let it sit fot about 20 minutes so its less likely to explode.