Breaking Bad, Season 1

[Walter is making home-made thermite in Jesse's kitchen for purpose of stealing methylamine.]

Jesse:
And that'll cut through a lock? Because this is supposed to be one big-ass lock.

Walter:
In World War II, the Germans had an artillery piece - it's the biggest in the world - called the Gustav Gun, and it weighed a thousand tons. And the Gustav was capable of firing a seven-ton shell and hitting a target, accurately, twenty-three miles away. [chuckles] I mean, you could drop bombs on it every day for a month without every disabling it. But, drop a commando - one man, with just a bag of this - and he could melt right through four inches of steel and destroy that gun forever.

[He tosses the bag of thermite to Jesse, who flinches as he catches it.]

Jesse:
Jeez.

Walter:
So yes, I think it'll cut through any lock we're likely to find.