Hurried back inside empty school with a growl (5)
I believe the answer is:
snarl
'growl' is the definition.
(I've seen this before)
'hurried back inside empty school' is the wordplay.
'hurried' becomes 'ran' (running is a kind of hurrying).
'back' is a reversal indicator.
'inside' is an insertion indicator.
'empty' says to hollow out the word (remove centre letters).
'school' with its middle taken out is 'sl'.
'ran' reversed gives 'nar'.
'nar' put within 'sl' is 'SNARL'.
'with a' acts as a link.
(Other definitions for snarl that I've seen before include "Growl viciously" , "Entangle wool - show displeasure" , "Show one's teeth (like a lion)" , "Growl aggressively" , "(Make an) aggressive noise" .)