Fractured

Toby mentions the possibility of a megaton blast. A megaton is equivalent to 1,000,000 tons of TNT. For reference the bomb dropped on Nagasaki was a 21 kiloton yield equivalent to 21,000 tons.

While underground searching for the gas leak, both Walter and Toby get leg injuries, and they tie themselves together (as in a 3-legged race) in order to be able to walk more quickly (to the tune of the song "More Than Words". However, in a subsequent scene in which Toby lowers a shipping container over an open manhole using a crane (so that they can create a chimney effect and assist in burning off the escaping gas), both characters are walking (and running) without any sign of injury.