me waiting for the long campaign's port

You have to be stealthy, like how 'prisoner' would do while escape, not to be detected.
If you get detected, alarm will activate, and enemy will spawn and come to you.
In HL2, this will lead to map restart because you must 'fight' those enemies without any weapon, only leading to player's death.

I've placed a Pistol. If you do things as the mapper expected, you won't need this anyway.
I've also placed a Oil Drum in the Control Room for helping people get inside of the vent.

These whould be enough. I've completed the map without any notable problem.

As I said, unless you spawn yourself some weapons (as I don't think this map will give you any weapons for you to deal with the soldiers), you may be unable to complete this map.

I believe that you are supposed to escape the prison and its guards without any weapons at all, which is pretty much undoable. I won't be adding this to my campaign collection. In other words, shame on the original author (Pandillez) for making me deal with the armed guards as a vulnerable unarmed person.

Besides, I found no walkthrough videos of this mod, so I had to figure how to progress through the map on my own.

How can I expect to take care of the guards without any weapons, at least until I reach the generator room?

I get this is meant to be an 'escape against all odds' kind of thing but the encounter in the cafeteria is legitimately one of the most BS encounters I've experienced. You open a door and you have a whole squad of Prison Guards with Pulse Rifles looking at you. This feels like a cue meant to say 'wrong way' but when I disabled AI awareness and looked down there I saw the player was meant to go down there. I'm okay with some guys overlooking the cafeteria shooting down at you but if I had to make a change to this, I'd make it where those guards chase you from one of the other hallways instead.

That encounter alone put me off on wanting to try the rest of this out.