Kurt’s dawning realization that this was a set-up is adorable.
It’s slow, starting from when the cheerleaders start playing with their cups, his eyes move, his mouth hangs open and then the band starts playing. Blaine points and Kurt looks up, a smile on his face. His boyfriend is ridiculous and partly embarrassing and he loves him with everything that he has.
Blaine looks at Kurt proud of his surprise and the songs words resonate with a truth that he believes for Kurt, “And now it’s time to build from the bottom of the pit right to the top, don’t look back.”
Kurt shakes his head at “I don’t ever wanna let you down” because how can Blaine, ever let him down?