SYND 16 3 77 HIJACKED PLANE AT ZURICH AIRPORT

In the video, two pilots in Iberia uniforms board a plane. A passenger finds it odd when one pilot doesn't respond to a request, which raises suspicion. Shortly after, a metallic sound is heard, and the passenger notices the pilots are involved in an unexpected situation in the corridor between first class and the cockpit.

What sound did the narrator hear shortly after the pilots entered?

Where were the pilots located when the narrator turned around?