Orphan Black kind of has an Ari Millen problem. These Castor clones are dropping dead left and right, and it seems to indicate that Millen isn’t quite up to the challenge of portraying so many different characters like Tatiana Maslany can. “Newer Elements of Our Defense” introduces yet another Castor clone as the literal brains behind the operation, giving Helena a chance to really shine in an episode that otherwise spends too much time spinning its wheels.

Last week, it looked like Mark was done for, but surprise! He’s still very much alive, left for dead in a corn field with a couple of bullet wounds. Seemingly offing a character just to bring them back in the following episode is a bit cheap and robs the act of its meaning and intended effect. That said, I like Mark the most out of all the Castor clones because he’s the only one with any real emotional depth or shading.

Sarah rescues him from the field much to his confusion, and is forced to remove a bullet from his leg in order to keep him alive so they can retrieve the Castor DNA.

Meanwhile, Rudy is on the hunt for the rogue Mark, and Gracie’s mother has reclaimed her and her unborn child in the name of the Proletheans, who have chosen a new leader. He seems a bit nicer than the last one, at least. When Gracie has a miscarriage, her mother disowns her — she doesn’t even spend an entire episode back with her family, and I’m not sure what the point of this plot is, other than a way to get rid of the baby (and judging from next week’s preview, it allows Gracie to team up with the Leda ladies).

The best stuff in “Newer Elements of Our Defense” resides with Helena, still trapped on the base and plotting her way out. She also gets back to her favorite pastime: eating!

That chicken comes in handy when she cleverly whittles down the bone with her teeth (her TEETH) so she can use it to pick the lock on her cell. But her escape is short lived when she comes across the Castor clone she spotted earlier (who seemed to have some sort of telepathic power?), strapped into a chair and clearly suffering. She removes the cloth from his head to discover that the top of his skull has been removed, with wires attached to his exposed brain. And then Orphan Black delivers a really great homage to Alien: Resurrection (I'm kind of amazed they chose that film, of all things, to reference), recalling the moment when Ripley stumbled across her clones, and the one still living and totally deformed begged her for a mercy killing. “Kill…me,” the Castor clone tells Helena.

And a sympathetic Helena obliges.

Helena has become one of the most complex and endearing Leda clones, and as Sarah describes to Mark later in the episode, Helena really can’t help how she turned out. Orphan Black is exploring a really interesting nature vs. nurture concept this season, and of all the Leda clones, Helena is the one the Castors should be able to empathize with most — a victim of a violent upbringing, Helena was trained to kill and received very little (if any) nurturing. There’s something childlike about her, from her eating habits to the way she empathizes with the weak, as if she’s stuck in a state of arrested development due to her lack of exposure to the “real” world.

Sarah and Mark learn that Johanssen impregnated his crazy cult-wife with some Castor DNA, but she miscarried the baby. So the new brother-sister clone team head off to a cemetery to grimly dig up the baby’s remains, when Rudy finds them and gets into a fight with Sarah. Mark appears to be dead or dying once again, and again he’s given a surprise resurrection. How many times are we going to do this?! Mark resumes his military seniority over Rudy, convincing his brother that he was merely working with Sarah to accomplish his mission — which is now accomplished. And as for Sarah…Orphan Black really is married to these cliffhanger endings:

Please, like they’d kill Sarah. This week really highlights the lack of genuine stakes on this series.

Less interesting this week: Cosima is pining over Delphine, still, and Felix resolves to get her on the Orphan Black equivalent of Tinder to help her find a “scratching post.” It’s cute, but eh.

Even less interesting: The Alison and Donny Show, which has now evolved to include Alison’s high school boyfriend, who is apparently a drug kingpin. This plot has absolutely no connection to Sarah & Co., and while it’s been cute and fun sometimes, it’s really detracting from the real meat of the season. Maybe they can kill off Alison so this show feels like it’s not messing around anymore.

Next week: Gracie gets a makeover and Cosima finds love. Also: more fun with a baby skeleton.