"Ooh, can I set off the contingency plan? You got to do it last time." "Alright, alright. Shall we get to the tunnels, dad?"<br/><br/>If he questions what they're planning, they'll quickly explain, as they lead him to an underground tunnel, concealed into the building, that they'd rigged both houses to explode, apparently killing them both in the fiery destruction, in the event that they needed to leave in a hurry. And now was as good a time as any.