Zombies got into my locked and barricaded building. How?
They smashed the barricades down with their hands, and a zombie with the “Memories of Life” skill was able to open the doors for them. Or if your barricades are still up and there’s a zombie inside, it’s likely that someone rebuilt the barricade but forgot to dump a dead body outside, and it’s risen. (Or that one of the other survivors in the safehouse was killed, perhaps through an Infection, and rose.
They smashed the barricades down with their hands, and a zombie with the “Memories of Life” skill was able to open the doors for them. Or if your barricades are still up and there’s a zombie inside, it’s likely that someone rebuilt the barricade but forgot to dump a dead body outside, and it’s risen.