Daniel wishes he'd thought about norebang earlier, since being alone in a dim room with Natasha is heaven. She flips through the songbook, too distracted to tell Daniel to not stare at her. When she leans over to punch in the code for her song, he notices marks from the couch on the backs of her thighs. She notices him looking at her, but Daniel doesn't care—he wants her to know that he wants her. He decides to get up and kiss her, but her song starts before he can. It's "Fell on Black Days" by Soundgarden, an objectively depressing song. Natasha loves it and belts every word. Her singing is horrendous.
Natasha's song choice again suggest that she's not opposed to passion the way she'd like to be, she just likes to experience it privately. In this way, agreeing to sing for Daniel is a major step in Natasha's journey of realizing passion isn't a terrible thing, as it's the first time she's truly willing to be passionate and allow someone else to see it.
When the song ends, Natasha looks shyly at Daniel and explains that she loves the song. When Daniel says that it's a bit sad, she insists that angst never hurt anyone. Daniel insists that Natasha can't possibly be full of angst, but she says she's just good at hiding it. When Natasha puts the mic down, Daniel pulls her towards him until she's in his arms. He tells her that her singing was awful and kisses her. He thinks the kiss feels like more than chemistry.
Natasha's admission that she hides her struggles is a major turning point for her, as it shows her finally beginning to confide in and connect with Daniel. Notably, this admission leads to their first kiss and their first real physical connection, which in turn connects a sense of trust to physical connection.