Twenty minutes in, I would have given it 2/5 stars. The earliest action sequences were awkwardly staged, and the whole beginning felt extremely rushed, with serious decisions and character moments passed over. Tessa in particular gets shorted; after 20 episodes, we know she's not a fighter, and not given to violence, but we get very little with her character's reaction, just a very short scene as she and Duncan are prepping traps, which comes fairly late in the game. Also, any kind of defensive movie, whether it's Die Hard, Fortress, or Home Alone, requires a sense of the ground that's being defended. Die Hard was absolutely brilliant with establishing shots that didn't feel gratuitous, but established the landmarks that allowed the audience to understand where they were and what they were seeing. Here, we never got a very good sense of the house, and where the action was at any given time. (Not that I expect an episode of any TV show to be up to the Die Hard standard. Still, even for TV this was a serious weak point.)
However, the episode really recovered from that point. The action sequences and pacing improved significantly, and the twist with Lori's skewering of her immortal stepfather's motives was very welcome. I can't even begin to count the number of shows where the rape/murder of the tough-guy protagonist's wife/girlfriend/daughter gives him an excuse to be violent without alienating the audience. (Braveheart, many Bond movies, Firepower, etc.) It was interesting to see the dark side of this pointed out, that ultimately, it wasn't about the girl at all, it was about HIM. This take is bolstered when ultimately, it's Lori who gets vengeance for herself, in the context of saving her stepfather. It winds up being a satisfying episode, despite the flaws. Kudos.