Vault Boy - Image #288,475

Because going outside and repairing bombs are exactly the same thing.

The point he was trying to make was that the Lone Wanderer would have never seen a nuclear warhead before (assuming you run straight from Vault 101 to Megaton), yet you can disarm it with no trouble. Hell, it's apparently more difficult to fix the leaky pipes around town than to disarm the frickin' nuke!