When Phineas says that they could have a lot of fun with Agent P, Major Monogram says "the next 15 minutes should be a real hoot." Some may think he's referring to the length of a normal episode, credits and all; but, with less than five minutes of show remaining, he's actually referring to secret agent policy that calls for Perry to be immediately moved to another home where his agent status is not known. He's saying that Phineas and Ferb have about fifteen minutes with Perry before they never see him again.