"...doubt it." If anything the extra noise was liable to give him...well, not indigestion, but if he were prone to it maybe. At least make him lose his appetite, which given his day would probably be the last straw.
On the other hand, there wasn't any real reason why he couldn't be civil. The kid was only doing his job, after all, and if he was especially...enthusiastic about it and felt the need to run his mouth the entire time...Okay, Bourne would really prefer he didn't, but it happened.
Nevertheless, he found himself clearing his throat to speak again. "I'm not a cop." He wasn't entirely sure why he offered the information, but it was innocuous enough, and if it would slow down at least some of the stream-of-consciousness coming from the kid he figured it might actually be worth it to say something now and again.