Heat up in a hurry (4)
I believe the answer is:
nuke
'heat up in a hurry' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nuke that I've seen before include "Attack with H-bomb (slang abbr.)" , "Destroy with a very powerful 18" , "Attack with an atomic weapon" , "Nuclear weapon (sl.)" , "Drop huge bomb on" .)