Spoiler alert: after doing the John Henry thing, in a robot-on-robot kind of way, the fellow and his shovel dig a basement but forget to dig a ramp, so they can't get out. So what do they do? Do they dig a ramp, then fill it back in?
They cut off the anthropomorphic shovel's legs and turn it into a furnace. Human Boss gets to stick around as the building's new janitor. Presumably they lower him a ladder at some point.
I mean really, W the F.
Anyway, as you can see above, the Central Subway crew did not make this mistake. No furnaces will be harmed. I'm not sure if they plan a rescue op for the tunnel boring machines, though, or if they're gonna do a Mars Rover on them.