The show On the Spot made by Roosterteeth is a goldmine of short form improv sketches. The show is a contest between a pair of 2 person teams, moderated by a host. The host runs several different short improv games, and awards points to the team he deems the better or more funny.
By all means, the show is hilarious when it follows this formula, but I find that some of the best moments are when a team instead of working together, one person decides to throw a wrench into the scene and totally mess with their partner. Watching someone immediately go from confident to utter confusion in a matter of seconds can be very amusing. In one scene, a team has to describe the plot of a movie based off of prompts while the host alternates who on the team is talking. The plot prompts are “Russia” and “Romance”, which proceeds fairly normally until one team member unexpectedly takes the scene to outer space, to the dismay of his partner. Right after their time is up, the partner shouts at his teammate “Why’d you go to outer space?”
So while I agree it’s important to follow the rules and guidelines for improv as described in Truth in Comedy, I think there can be times when having a partner turn on another can be just as or possibly more funny than normal.