He might save you from disorder starting in army hospital (7)
I believe the answer is:
messiah
'he might save you' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'disorder starting in army hospital' is the wordplay.
'disorder' becomes 'mess' (messing is a kind of disordering).
'starting' says to take the initial letters.
The first letters of 'in army hospital' is 'iah'.
'mess'+'iah'='MESSIAH'
'from' is the link.
Can you help me to learn more?
(Other definitions for messiah that I've seen before include "Gospel saviour as prophesied" , "Expected deliverer of the Jews" , "A hoped-for saviour" , "Leader, saviour" , "Handel's composition, sung annually by Our Lady's Choral Society" .)