Probably the main reason why I keep watching Warehouse 13 is because it has such a positive, upbeat message about cooperation. The show's heroes solve their problems by working together, and by being a family. And the show manages to spread this message without (usually) being too cornball — if anything, the characters often bond over how they're doomed to go crazy or be killed.
So in this worldview, the worst thing you can do is to push your friends away and refuse to share your burdens with them. Which appears to be the main thing the show is exploring this season. Spoilers ahead...
It's becoming clearer that the "evil of his own making" that Artie is facing this season on Warehouse 13 involves not just deadly artifacts disappearing from the Warehouse — possibly with Artie's unconscious collusion — but also Artie becoming paranoid and isolating himself from everybody else.
Artie feels like he can't tell people about the events of the season opener, where the Warehouse blew up and he used the astrolabe to turn back time 24 hours. (Although, to be fair, the only reason Artie can't tell anybody is because Brother Data told him not to. And he's not exactly obeying Brother Data in other respects, is he?) And meanwhile, he's still having paranoid visions about Claudia stabbing him with a magic knife, causing him to act twitchy and weird around her. And he's convinced someone in the Warehouse is helping Brother Data to steal artifacts, which makes him extra paranoid and ranty.
So this episode actually shows us Artie having a shot at happiness and companionship — we start off with a scene of cozy friendliness, with Artie being really sweet to Steve and asking when was the last time he slept. Artie promises to help Steve figure out how to get himself off the resurrection metronome thingy, and then there's a nice moment where everybody razzes Artie about the fact that he has a girlfriend now. (And the cast basically proves that they're the goofiest cast on television.) And for the rest of the episode, Artie is steadily getting closer to a real relationship with Vanessa, who's especially awesome and nice this time around.
Leaving aside the fact that we haven't seen Vanessa in ages, and suddenly she's supposed to be Artie's full-on girlfriend, the episode does a pretty great job of building up the idea that this could be a serious relationship that becomes an ongoing thing on the show. And then it's snatched away, because Artie decides that anyone he has a more than Platonic relationship with will be in massive, huge danger as long as he's under this astrolabe curse thingy. (Even though, as Vanessa points out, she's already a Warehouse employee and thus bound to be in danger in any case.) As Vanessa says, "Cutting yourself off from the people who love you is a terrible idea."
Artie's realization comes as a result of Alice Liddell escaping from her mirror and going on a crazy slutty Harley Quinn-inspired rampage, jumping from body to body in an attempt to kill Artie. Why does she want to kill Artie? (Or torment Artie, by hurting the woman he loves, I guess.) It's not entirely clear, but it seems to have something to do with the astrolabe curse, and the notion that Artie is trapped in an evil of his own making. Did Alice just magically decide that Artie should suffer, or did the person who stole the mirror from the Warehouse convince her? (She also hates the Warehouse generally, so it's not that much of a stretch.)
Meanwhile, this episode continues the show's proud tradition of completely riotous dialogue, including Artie's "Oh yes, that's what we want. Children." Pete, in particular, is really settling in as the show's comic relief this year, with great lines, like: "I have been doing a lot of crunches." "Linda Blair's career was never the same." And "I have ideas. Most of them are illegal."
Oh, and Claudia has installed pneumatic tubes in the Warehouse! Is this new, or have we seen this before? In any case, yay!