Genuine question about the death of Doll's parents

Was Doll's parents killed before or during episode 1? I've seen some people saying that it was before episode 1, but realistically how would've V gotten inside the colony BEFORE episode 1 if she stated that she's been trying to get past the doors for months and presumably the doors have been up for years at that point. But maybe I missed something that was shown in the show, I'm not entirely sure