as the machine is pulling Alien Zim back to his reality, he can hear the sounds from where he is in his world.... which should tell you something
edit: holy crap, guys stop asking if there's going to be more. THERE'S GOING TO BE MORE.
pg 1: [link]
pg 9: [link]
Pg 11: [link]
Invader Zim (c) Jhonen Vasquez