Swamped

The newcomer immediately backs away on seeing Mackenzie and Arthur. The couple walks to one side, and the newcomer walks out of the scene, towards the center of the stage.

"Can't believe it!" they say incredulously. "The house was supposed to be empty! This was my chance to slip in and find that fortune Mackenzie refuses to spend! But I had no luck, and I took too long, and now they're both back! Not like I can take anything else, either - it's all cheap stuff. I'm going to need to wait until there's a good chance to slip out."

And with that, they hide behind the last chair, before Mackenzie and Arthur take the focus again. The arguing resumes, and several chair-swaps happen, until it gets to the point that the mistress and the burglar attempt to swap chairs and collide right with each other.

This, of course, makes such a loud noise that the other two promptly turn to look at them.

"Who in blazes are you?" Mackenzie asks angrily.

The woman panics, and gets up.

"I'm terribly sorry. You see, our employer heard about your roof, and wanted to surprise you by paying us to repair it while you were out. But then you came back earlier than we expected, and it was a bit more complicated than we thought it would be, so we hadn't gotten past taking measurements yet..."

"What she said," the intruder agrees readily. "Sorry. I knew this was a terrible idea, but our employer insisted on secrecy, so here we are."

"Hmmph," Mackenzie grumbles. He's clearly unconvinced. "Secrecy. A very convenient excuse for not telling me who this supposed employer of yours is, hmm?"

"Oh, that's simple," says a voice from offstage. "It's me."

And thus Matilda Laikenne makes her entrance.