In a sense, this a reckoning for Doofenshmirtz on what kind of villain he wants to be. It's sort of like Hego grappling with the Golden Age of superheroes ending but from the other side, with the monologues and the showmanship and the wink-and-nod escapes at the end of every episode. Back when there was a status quo to play with.
Doofenshmirtz is playing a different game now. He can't monologue and rampage through the streets, he owns those streets. LOVEMUFFIN don't get that, but I think this could be the moment that Doofenshmirtz wakes up. They want to keep playing mad scientist, but reality is ensuing. The world's changed, kids, and if you can't change with it you're gonna get left behind.
Next turn would be a really good time to build on that character development by, for example, giving up on playing King of Doofania. At least that's how I'd play it.