What would it feel like to die by being in a spacecraft that breaks up reentering the atmosphere?

After Endeavor reentered the atmosphere today with that gash on it's protective tiles, it made me think of the Columbia tragedy of 03. I was wondering if someone could explain to me what it might feel like to die that way. I understand that no one can explain it fully because no one has been through it and survived to tell about it, but with what we know about atmosphere, could someone possibly hypothesize what they think it might feel like?