He still has a lot of programming to do when it comes to human interactions. Case in point, when the man he approached turns and says sorry but holds the tone of a question, T-800 does not understand.

"What." Which could also be a question and technically it is but his vocal processor does not have the same range of function that mankind possesses.

He wants to understand man, honestly. His curiosity just doesn't read in his expression or voice. Maybe he will clarify. "I do not understand why you are sorry."