Part of the conversation is: "Only problem is, most of the bedrooms were gone already. Was there any particular dorm you were interested in?" Why did the speaker use past tense "was and were" to ask the other one during a conversation happening at present from their perspective? Please help me.
It is hard to account for why cultures have their linguistic quirks, but here is my sense.
When someone asks such questions in the past tense, they are implying that they possibly should have already known the answer, and you might already have told them or written the information on some form. It is, roughly, a way to acknowledge the burden of making the customer explain themselves. In American English, such use of the past tense strictly a feature of institutional politeness, typically customer service agents speaking to customers.