Spock (Ethan Peck) has always shown some musical inclinations, even back during “The Original Series.” He plays a Vulcan lute in his spare time; this season revealed that it was prescribed to him as a coping method for his emotions. We’ve never seen Spock singing along as he plucks the lute’s strings, but “Subspace Rhapsody” reveals that isn’t due to lack of talent.
Spock is the first crew member to break out into song during the first group number, “Status Report.” Seeing an emotionally-restrained Vulcan singing underlines the surreality of the musical; normally, Spock would be the least likely to express himself so overtly.
He gets a solo later in the episode, right before Uhura’s: “I’m The X.” The title’s meaning is twofold. For one, Spock is the ship’s science officer, so he’s always trying to solve the unknown like an equation. It’s also a pun on how Christine Chapel (Jess Bush) has chosen her career over continuing their relationship. Spock’s feelings of betrayal tie the meanings together; he’s decided that giving over to his emotions yielded disastrous consequences so he will return to cold analysis.
“I’m The X” is one of the calmest heartbreak songs I’ve ever heard. Underscored by a dour electronic tune, Peck maintains a strong and even timbre while moving his face as little as possible; Spock’s shields haven’t dropped even under these circumstances. Yet somehow, you can still feel the rawness in his voice.