Hello everyone
I'd like to ask about the phrases "ain't like one of us is up there" and "pointed in the large hole in the window" in the following context.

He looked up and saw the Noddie hiding under the escalator who was drawing a bead on the three taking point. Vega raised his GD2 to fire.
Before he could pull the trigger, the soldier was riddled with bullets. Looking across, Vega saw that Gallagher had taken him down.
"Nice shot, Gallagher," Goodier said.
That should have been my shot, not that stupid bint's, Vega thought.
Momoa started shooting when they were three-quarters of the way up, firing in several directions at once.
"The hell, Pup?" either Kim or McAvoy said. Vega couldn't see either of their chestplates.
Shrugging his massive shoulders, Momoa said, "Just figured I'd be sure. Ain't like one of us is up there."
"Looks like you got one," either McAvoy or Kim said.
When Vega got to the top of the escalator, along with Gallagher, Brodeur, and Bowles, he saw that there was a Nod soldier slumped over a railgun that was pointed at the large window - or, more accurately, in the large hole in the window. That's where the broken glass came from. And all that railgun fire.

Does the phrase "ain't like one of us is up there" mean "I'm sure that there are no our soldiers up there?"

And does the phrase "a railgun that was pointed at the large window - or, more accurately, in the large hole in the window" mean that the railgun was shoved through the hole in the window?