I tried to complete the quest saving the girl, but no matter what i do and in which order, the quest fails.

i found out about the compound, before leaving the covenant i talked to the mayor and persuaded him for more info. he said, he would tell the compound that i am coming and i should talk to someone there. but everyone inside is immediatly hostile once i enter. so i killed every guard until i reached the head scientist which finally talks to me.

i declined her offer, but i can't finish the quest. no matter if i

kill her -> talk to the girl -> open the cell

let her live -> open the cell

let her live -> talk to the girl -> open the cell

the quest always jumps to "find old man stockton" and fails 5 seconds later.

any clues as to what i am doing wrong? do i have to side with the scientist to complete the quest?...

The town is hostile by default. There's no way around that if you free Stockton's daughter. The only way to keep the town friendly is to keep the daughter captive.

You probably failed because Old Man Stockton is most likely killed in the fight with the townsfolk.

Shouldn't the old man be in bunker hill? how can he be killed there?

i read that covenant becomes hostile once the girl is freed, but why would the guards inside the compound attack me if i managed to persuade the mayor? every google search about the quest said, go inside the compound and talk to the guards... but since i get attacked by them i guess there has to be either a bug or i did something wrong...