Death caused by lag spikes on minecart over a lava field.

I was with my minecart over a lava sea, up 5 blocks, from the sea level and i had a lag spike for the amount of lava on the screen, suddenly i start burning and i died for suffocating inside a wall.
Tried this twice and always happens.
I hope you understand this even if my english is not very well..
Thanks, keep up the good work!

EDIT :

I was on this map :

http://www.fileswap.com/dl/ymM3oBLedw/Super_Hostile_01_-_Sea_of_Flame_II_v3.0.zip.html

It's the Super Hostile map Sea of Flame II...i was trying to reach the GIANT PIG STATUE with the Minecart from the Monument Hall.