Title text:
That was quicker than usual! The cabin's sprinkler system often makes it really hard to keep anything lit.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3114/
I feel like the last panel especially builds on the joke by continuing to divert expectations. It goes from humorously building too accurate of a log cabin, to coming back around to accidentally/on purpose starting a fire, thus completing the initial request.