Are they all model patients in it? (5,8)
I believe the answer is:
dolls hospital
'are they' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs sometimes mean the same thing.
'all model patients in it?' is the wordplay.
I cannot really understand how this works, but
'model' could be 'doll' (a doll is a model of a person) and 'doll' is found in the answer.
'it?' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for dolls hospital that I've seen is " Place repairing certain toys".)