Put the summary of the bug you're having here
I was traveling down my nether rail to my fortress base when I encountered a blaze. It fired at me and I hit it with my sword as I passed. I didn't kill it and was coming to the end of the rail line, so I hit shift to hop off, so I could finish off the blaze.

What I expected to happen was...:
I should have exited the minecart and been able to engage the blaze. There were no holes in the floor.

What actually happened was...:
Instead, when I hit shift, I was glitched through the floor and fell into a lake of lava below. With no where to go, I burned up.

Steps to Reproduce:
As this was my hardcore map, the world was deleted after I died and I cannot go and try it again. Nor can I get my freaking world back...