The bug

Creepers are capable of stopping their detonation if the player has gotten too far away. However, it seems that the only check is whether the player is nearby, and not whether or not the player is in Survival mode.

Steps to reproduce

1. Go near a creeper in Survival mode
2. Back away as soon as its fuse starts
3. It doesn't explode
4. Go near the creeper again
5. Switch to creative mode as soon as its fuse starts
6. It explodes