You can see the tweeting from the canary in the middle panels showing they can still hear it singing with Snow White from outside the mine, leading them to not realize that there had been a gas leak
Commentor probably never set foot in/on a mine. I realize the whole purpose is that the lack of noise indicates danger. Cannaries have been replaced by 4 head gas monitors.
If you do actually want to talk mining, though, I'm your guy.
You can see the tweeting from the canary in the middle panels showing they can still hear it singing with Snow White from outside the mine, leading them to not realize that there had been a gas leak