Direct object or adverb?
Solution 1:
It is not a direct object or an adverb, because of being followed by the preposition ,"in", and therefore makes the phrase a prepositional phrase/an adverbial [of place].
for instance
-
in/to hospital
-
in/to church
And so on....
As I was saying, I can't call it "an adverb" unless we are talking about words such as: "nowhere, anywhere, everywhere, wherever, there, here, etc." Those are referred to as "Adverbs Of Place".