Disorder puts part of US hospital in no end of peril (7)
I believe the answer is:
derange
'disorder' is the definition.
(deranging is a kind of disordering)
'part of us hospital in no end of peril' is the wordplay.
'part of us hospital' becomes 'ER' (short for emergency room).
'in' is an insertion indicator.
'no end of' means to remove the last letter.
'peril' becomes 'danger' (synonyms).
'danger' with its last letter taken off is 'dange'.
'er' going within 'dange' is 'DERANGE'.
'puts' acts as a link.
(Other definitions for derange that I've seen before include "Make insane" , "Make mad" , "Unhinge" , "Remove from order" , "cause confusion" .)