Glenn meets his demise in the comics during a particularly intense and chaotic event. The circumstances surrounding it are quite harrowing and have a significant impact on the story's direction.
Negan's death in the comics occurs at a specific point, but I can't recall exactly when off the top of my head. You might need to do a detailed search or refer to dedicated comic forums for the precise moment.
Iron Man meets his end in a particular comic arc where the circumstances are both intense and unexpected. It's a turning point that shakes up the entire comic landscape.