I don't know if many people noticed this, but recently I was doing a hardcore world.
Keep in mind that when you make a hardcore world, you cannot activate cheats or spawn a bonus chest.

Anyway, I was really struggling in my hardcore world, so I decided to give myself some stuff, forgetting that I didn't have cheats enabled, or that I couldn't. Then I thought, if I open my world to LAN, then would I be able to use cheats? So I opened my world to LAN and set cheats to be enabled. This works. Knowing that, I could spawn me up some stuff to keep me going.

Later when I was battling the Ender Dragon, he knocked me off one of his towers while I was trying to destroy his Ender Crystals, and I fell into the void. I died in the void. So then, I had the choice to either go back to the main menu, or spectate my world. I clicked spectate, to see how far I got, but then a thought came to me. What if I use the gamemode command here? I tried going into survival mode, and it worked. I was able to gather supplies once more, and try my fate at the Ender Dragon once more. I logged out of the world to see if my world would still be there, not that It was a glitch. And yes, you can log back into your world. Talk about escaping death.

Again, I don't know if anyone else tried this, but I found this cool, as one of the challenges of a hardcore world is no respawn. This must be something Mojang hasn't thought of yet.