A bit of a riot at the detention centre can be the devil! (5)
I believe the answer is:
demon
'be the devil' is the definition.
(thesaurus)
'a bit of a riot at the detention centre' is the wordplay.
'a bit of a riot at' becomes 'demo' (I am not sure about this - if you are sure you should believe this answer much more).
'centre' means to look at the middle letters.
The centre of 'detention' is 'n'.
'demo'+'n'='DEMON'
'can' is the link.
Can you help me to learn more?
(Other definitions for demon that I've seen before include "Imp" , "beast" , "Fallen angel" , "Fanatic; devil" , "See 3" .)