Turner in endless panic (5)
I believe the answer is:
lathe
'turner' is the definition.
(a lathe is something which 'turns')
'endless panic' is the wordplay.
'endless' means to remove the last letter.
'panic' becomes 'lather' (as in a phrase like 'in a lather').
'lather' with its last letter removed is 'LATHE'.
'in' is the link.
(Other definitions for lathe that I've seen before include "Wood-shaping machine" , "8 [TURNER]" , "piece of machinery" , "Turning implement" , "Machine tool for shaping metal or wood" .)