Normally, being trapped in a small, freezing room with a black pudding is bad.
Black pudding saves butcher trapped in freezer
But this butcher was able to leverage destructive powers of the pudding to save himself. A door? No problem, those suckers do 3-24 damage in AD&D. This butcher must have rolled extraordinarily well on his Reaction Roll for it to get it to help.
Perhaps he'd taken some advice from Gary Gygax, who wrote a war story called How to Tame A Black Pudding (link to Grodog's resources) back in Dragon 289.
(A real black pudding)
Either way, it just goes to show you can't just paint all oozes out to be horrid, vile, unfeeling foes. Sometimes they can be horrid, vile, unfeeling friends!