why dose this map make it so i can turn in vehicles?

Played Collapse first by accident, really fun map, but it just sorta "ends" out of nowhere unless i'm failing to understand.
Killed a gunship, used a turret to shoot a bunch of soldiers, then it was just endless ones spawning one at a time above me, thought i was supposed to jump down,
did so, only for fade to black.

That's your environment's problem. I just played the second map myself, and I could complete the map without any game issue.

The 2nd map perma-freezes your entire game and computer, I do not recommend

In general, you can separate maps from 'Other' tab. But because of how GMod sorts maps with category, I can't separate these map from 'Half-Life 2'.

You can see my other addons without that kind of warning already did it.

I can make a PR to GMod to fix it, but I'm too lazy to do it for now.

"Warning
Even though I've tried to separate maps from this addon from Others tab, it will still be categorized under 'Half-Life 2'. I think this default behavior cannot be overridden."
Bro it's because map names starts with "d3_".

I did not get out of that building.

I don't think we are supposed to get out of the building. Some brush in outside of the building is missing texture. Since G-Man doesn't say anything, all we can do is either jump down to the small gap between building, or wait for the map to finish.

When I go to the top of the building where I am supposed to fight with the gunship, I get stuck as the gunship did not destroy a building as it is supposed to, leaving me in a softlock that I cannot get out of.