Drive in, some claim, pell-mell (5)
I believe the answer is:
impel
'drive' is the definition.
(I know this)
'some claim pell-mell' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'IMPEL' can be found hidden inside 'claim pell mell'.
'in' acts as a link.
(Other definitions for impel that I've seen before include "Make" , "Spur on" , "Constrain" , "Oblige" , "'Drive, force (5)'" .)