Macha (can be found at Tea at the Ford) has meta about the three episodes: Pangs-IWRY-Something Blue. In Pangs, Spike wants in, but Angel hanging around outside NOT asking to come in. In IWRY, Angel doubles down on wanting to stay outside (however nobly you read his intentions). In Something Blue, Spike doubles down (in a magically induced way) on his desire to really come in, thereby setting up the contrast with Angel.

If it's an accident, it's a pretty accident.