Nicotine misused outside hospital in a risky location (2,4,3)
I believe the answer is:
on thin ice
'a risky location' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'nicotine misused outside hospital' is the wordplay.
'misused' indicates an anagram.
'outside' means one lot of letters goes inside another.
'hospital' becomes 'h' (abbreviation for hospital on maps).
'nicotine' anagrammed gives 'ontinice'.
'ontinice' placed around 'h' is 'ON THIN ICE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for on thin ice that I've seen before include "In a precarious situation" , "in danger of a soaking?" , "sailing close to the wind?" , "Insecure" , "In a dangerous situation" .)