Allow nurses to depart — it could be a slippery slope? (8)
I believe the answer is:
gradient
'slope?' is the definition.
(I've seen this before)
'allow nurses to' is the wordplay.
'allow' becomes 'grant' (synonyms).
'nurses' is an insertion indicator (nurse can mean to hold onto or harbour).
'to' becomes 'die' (I am not sure about this - if you are sure you should believe this answer much more).
'grant' placed around 'die' is 'GRADIENT'.
'depart it could be a slippery' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for gradient that I've seen before include "Level of steepness" , "Third OT book" , "Angle of slope" , "Bank" , "Rise" .)