Those of us in the theater thought that something was about to happen. But no new footage comes up. Only the sound. What kind of sound is it? It’s a distinct “ting,” that sounds very close to the noise Tony Stark (Robert Downey Jr.) makes while working on his initial suit of armor in the cave in Jon Favreau’s Iron Man. Is this what we are hearing? Is it an audio tribute to Stark, because the MCU started with Iron Man, and should end with Iron Man?