halacha - Could a Cohen burn a body to escape the impurity?

Excuse the extreme hypothetical, but:

If a Cohen were locked in a room with no windows and a dead body, and just so happened to have lighter fluid and a pack of matches (and there were small holes in the ceiling for the smoke to escape), should he/could he burn the body in order to escape the prohibition of being in the same enclosure of a corpse (Rama YD 372:1 - the prohibition is not just to enter a place of impurity, but also to remain there)?

In more general terms, would alleviating his prohibition of being with a corpse override the seeming denigration of the body through burning it¹?

(I've heard before that in such a situation, the Cohen would be required to actually eat the body in order to get rid of it, but even if true it seems rather impractical, as he would have to eat practically all of the bone mass as well.)

^{1 Yes I am aware that the issue of burning a body does not have such a clear source}