> Try to make a joke to lighten the mood.
It’s way too awkward to just outright ask her what’s wrong. Better to go subtly bring it up at a later occasion, but for now, just do your best to perk it up.
[> Actually, let's turn off the music.]
Maybe wait for the guy to get to what you think might be the chorus, as a courtesy, but definitely turn off or turn down the music. That'll let the man know that hey, someone's in here and also avoid a possible stabbing.