Confusion, disapproval, awkward amusement. It's really uncanny the kind of range Spock has with one stoic expression. Normally he would have ignored the random song and accidental broadcast, but this one was intimate and perhaps an ounce of him sympathized with sharing such a moment with the entire city.
"It would appear that your Tablet is broadcasting."
[ visual ]
"It would appear that your Tablet is broadcasting."