He didn't kill himself in the actual game. But in the original Japanese pokemon Red, Green, and Yellow, Buried alive was an actual glitch.
If the player defeated his pokemon (A Muk, A Gangar, Two White Hands and sometimes Ash's Pika (which is a bloody and decaying Pikachu)) the game would totally freeze and you'd have to start all over again.
But if player lose, Buried Alive would say something along the lines of:
"Finally....Raw Meat". And he'd dragged the player in the ground. The final image is a picture of the player getting devoured by Buried Alive with the caption: "Game Over".
So in the game, he did not actually kill himself, but the artist decided to be creative and show this version of one of the Myths of Lavender town.
Hope this helps
Candle light gives nice atmosphere to comic. Im sad that there aren't scary things like this in released versions. Well... by going into data you can find all the white hand etc. but children games are way too boring without something spooky. Old chateau had also cool atmosphere in pokemon diamond/pearl.