I got the same message about no screenings in my area. Bleh.
Also, Vadic was clearly doing a ritual to contact the BBEG, where as she could just call the freaking borg or even Slipstream/transwarp over to them. The BBEG is clearly something different, powerful, but can't act on their own yet for some reason. That makes me think paranormal or something like a powerful being that is trapped liked in Star Trek 5. If that is the case, then I want to see Kirk show up with the Enterprise A to blow it up again. Regardless of all that though, Jack is the key to the BBEG for some reason, and I hope that we find out this episode.
Well, it's this or the next. We're cutting it rather close. I don't think a reveal with due impact, a satisfactory end to the conflict, and anything but the most abrupt resolution could fit into one episode, and although the next episode might jump away to some other character for a scene or two, it's going to have to get back to Jack's door before the first commercial break. So just structurally, I think it's kinda obligatory that we're about to find out. Then again, I also just really hate rushed endings.
The ritual is quite strange and I love that the first time we saw it was before we found out that Vadic was a shapeshifter, to make it extra viscerally unpleasant. That said, it seems entirely possible that Vadic didn't choose the form of communication and that for BBEG it isn't any less convenient than a viewscreen call. Maybe it's an interociter with a big torture button on their end. It's definitely a form of communication that relies entirely on Vadic's own body rather than anything to do with the ship (and seems to be the BBEG taking direct control of her hand goo, since she couldn't control her detached hand herself any more than any other changeling, and if the BBEG can do that, it might also explain the torture beam mode.) The vibes of dark cultic ritual certainly would suit some unphysical superbeing, and perhaps they would be best suited to create a form of communication that works over interstellar distances without requiring external hardware. Technically we've already seen Vulcans do that in Discovery but I don't think even CBS considers that season relevant canon anymore.
Edit: Still a possibility it's a technology of some kind, though. Just something that BBEG had to have put into Vadic at some point.