The noun is not required to be the subject or object of the sentence. It can function in other roles. Parallel structure does help to determine certain expectations, however. If you have two clauses with a pronoun in subject form in one clause, the expectation is typically that it refers to the noun in subject form in the other clause (assuming the two match in number - singular or plural).
The buildings are condemned, and they will be torn down tomorrow.
Fine. buildings = they, both in subject form
The building commission condemned the buildings, and they will be torn down tomorrow.
This is still okay, because "they" cannot go with the singular "commission," so "they" can only go with the plural "buildings."
The building commission members condemned the buildings, and they will be torn down tomorrow.
Er. This is not okay. Given a choice between two plural nouns, the structural expectation is that "they" should match in case - that is, "they" should match with "members" because both are subjects. But that doesn't make sense logically. Logically, "they" should match with "buildings." So we have a mis-match: structure points one way, while logic points another.
