[Pizza]

Originally Posted by timun

One could argue...

Spoiler!

... Hopper alerted Comrade Terminator to his location when he fired the AK into the ceiling to get the scientists to leave the control room, so the delay due to Dustin having to sing to/with Suzie didn't matter anyway.

Counterpoint...

Spoiler!

So much noise has been made in the Russian underground base (crawling through the air ducts, casually yelling and screaming in it; strolling through the long corridor, also yelling and screaming throughout) that I'm quite convinced each room is stand alone sound proof from each other. Gunshots wouldn't have alerted anyone if the other stuff haven't