### Clue: Tip of elbow nurse must keep very, very still (4,2)
### Answer: EVEN SO 
 ### Explanation: Definition: still
 [**1st letter of**(Tip of) "elbow" + EN(abbrev. for "enrolled nurse") ] **containing**(must keep) V(abbrev. for "very") + SO(very/to such a great extent).
Defn: …, as in "Still, there is no cause for that".