How do I free the rejects, what am I doing wrong

[snek]

Hello, I'll try to be brief even though there's a lot to unpack.

So I was at that point in the game where the faceless attack the institute(tremors started). I spoke with the faceless I saved and got the warning. Then I crawled through a vent that leads to the place where the rejects are. I killed everyone and then tried to free the rejects.
The way I understand it there are multiple options on on how to make them leave.
I wanted to tell them about the hole, but that conversation option didn't show up. Next option would be stealth (I am at effective 159) but that option doesn't show up either. I only got the persuasion check which I can't do because I don't have it high enough. Then I read on the internet that you need to interact with the hole before it shows up. I was sure I did that but went back anyway to do it again. That didn't work.
I reloaded a previous save. This time I got warning from the faceless. I went back to the hole and even jumped through. Made my way back to the institude and warned eiden out of curiosity, didn't tell him about faceless motives or that they spoke to me. After that I went to that area with the rejects again, and killed everyone, again. I made a save before speaking with the old reject. The persuasion check is still the only option I have. (I've read that I needed to get Nevil's help for me to be able to tell them about the hole, which I'm a) not sure if I did, but he's still definitely alive b) don't understand what good that does when there's clear path with no enemies to freedom)
On a side note, is this even one of the correct options? Do I HAVE TO stay on the good side of the institute or am I free to shoot them at this point? Will I be able to finish the game? And how the heck do I convince these buggers to get out of those damn cells?
Any help would be appreciated. I've enjoyed the game with no issues so far, but this is really annoying me. I have no clear directions beside helping the Tchortists, which I don't want to do.

[PaposikG6]

Rejects understandably are not to eager to trust a random stranger to help them so if you didn't ask Nevil for help, you need to pass a Persuasion check first in order to convince them.

Murdering all Tchortists in the area could possibly work as well(haven't tried it myself) but keep in mind that it will turn entire Institute hostile so you will need to fight your way through later.

Btw. don't worry about 'helping' Tchortists, it doesn't matter in the last location of the game how you treated them. Keep in mind however that once you enter the last location of the game you cannot go back till you finish it, so you might want to get some supplies for he journey first.

[Arclight]

Rejects understandably are not to eager to trust a random stranger to help them so if you didn't ask Nevil for help, you need to pass a Persuasion check first in order to convince them.

Murdering all Tchortists in the area could possibly work as well(haven't tried it myself) but keep in mind that it will turn entire Institute hostile so you will need to fight your way through later.

Btw. don't worry about 'helping' Tchortists, it doesn't matter in the last location of the game how you treated them. Keep in mind however that once you enter the last location of the game you cannot go back till you finish it, so you might want to get some supplies for he journey first.

I tried to go back to the Institute via the pipes, and found the route blocked by debris. I guess its closed, as you finish DC?

[PaposikG6]

I tried to go back to the Institute via the pipes, and found the route blocked by debris. I guess its closed, as you finish DC?

Once you finish DC, all paths leading to the Institute are closed

[Vokial]

Might not matter now after a few weeks, but I recently did this. It might require a certain build however.
First off, I tend to explore places wherever I go, already saw the Rejects before meeting with Nevil, who I convinced to help me free them.
Then I went tothe cells, checked the vent down the corridor that led through an orange corridor (that included a nice oddity) ending up in an area of the west wing of the Institute and killed the spiders again (not sure if that was needed).
Unlocked the cell doors through the terminal and talked with Sharp about them leaving and the option came up to sneak them through the vents. After choosing that, the game did it for me. I never needed to lure any guards to a different part of the map, it was super smooth. I suppose this requires some level of base Stealth though and certain PER to notice the vent leading out.