Further hammering home how sympathetic a character Li H'sen Chang is, and how much of a jerk Weng-Chiang is, we feel even more pity for the stage magician after Weng-Chiang dismisses him from his god's service. Despite this critical setback in their relationship, Chang still tries to appease his master by delivering The Doctor (dead, preferably) to Weng-Chiang, but Weng-Chiang will have none of it.
But it's Weng-Chiang's next action that really sets his character apart from all the other villains and meglo-maniacs in Doctor Who history. He was already clearing out his underground lair underneath the Palace Theatre to set up shop in the House of the Dragon and resume his search for the Time Cabinet. But he decides to stay behind and humiliate Chang and ruin his reputation - killing both Chang's assistant and stagehand Casey, then having Casey's corpse spoil Chang's live stage show and effectively end his career.
Weng-Chiang had vast powers, and the minimal powers that Chang had were only present because Weng-Chiang has bestowed them upon him, and yet he still felt it necessary to destroy Chang - an insect in his world. Seldom has a Doctor Who villain been so petty and vindictive, and seldom has a villain been so feared as a result.
Like the whole story so far, though, such dark elements are balanced with even more delightful scenes between The Doctor and Litefoot and, especially, the scene where Jago speaks with The Doctor at the theatre. Not once does The Doctor avert his gaze away from the goings on in the theatre, while Jago gradually has his dreams of a vast army of police officers crashing into his theatre dashed as the conversation goes on. At the end, when The Doctor affirms that he and Jago will "face their destiny standing shoulder to shoulder", it begins to put ideas of heroism in the mind of the previously cowardly Jago.