Medical student trained to be so humane (8)
I believe the answer is:
houseman
'medical student' is the definition.
'trained to be so humane' is the wordplay.
'trained to be' indicates an anagram (to train can mean to grow something into a shape).
'so'+'humane'='sohumane'
'sohumane' with letters rearranged gives 'HOUSEMAN'.
(Other definitions for houseman that I've seen before include "Intern" , "Junior doctor in US" , "Junior hospital post" , "Resident junior doctor in hospital - so humane" .)