The Doctor pinched his brow in frustration at his friend's childish antics. While the Time Lord had sat in the Cloister Room, brooding over their current situation, Adric had pulled the TARDIS down to the floor, landscape like, and laid on top of it as a sort of make shift bed.
As the Doctor pulled the Alzarian to his feet, he had an idea. "Wait a moment! Wait a moment, Adric!" the Doctor beamed. "You've just helped me figure out an end to both our suffering."
The Alzarian perked up at this. "Yes?" he said, happy at the thought of solving the answer. The Doctor moved to open the door of the TARDIS now lying on the floor.
"The Master's TARDIS has materialized inside our own, yes? Thus creating a recursive loop of TARDISes, yes?" the Doctor said, rhetorically.
"Yes?" Adric prompted.
The Time Lord then pushed Adric backwards and down the loop of TARDISes. An echoing yell could be heard for miles as the Alzarian fell deeper and deeper into the abyss.