I've just this second finished watching the episode, so don't expect anything too coherent here.
I've never been a huge Druitt fan, but this was a really good episode. I have to admit though, that I love Ripper!Druitt much more than I should. He's so awesomely evil, that scene where he killed the empath woman he was really scary.
We get to find out what happened to him to turn him into Jack the Ripper too, which is good because it makes things make a lot more sense. The evil entity possessing him though, kind of made me think of that Star Trek the original series episode, Wolf in the Fold, that claims that Jack the Ripper, along with many other mas murderers, was an ordinary man possessed by an evil creature. I've not seen that episode in years, but I remember that when I was a kid it actually scared me.
So, the evil, murderous entity is freed from John's body while Helen revives him, and finds a new home in the Sanctuary's computer systems, where it isolates the inhabitants and sets out trying to murder them all.
Druitt saves the day by taking the creature back into himself and teleporting away. And we don't get to find out what happens to him. We don't actually see him die, but at the start the writers make sure we know there's a good chance he has "Without detailed knowledge of the vessel, arrivals can be tricky. I need a known destination." Implying that teleporting without a known destination isn't exactly a great idea. And then at the end "I have no destination in mind." So what happens after he de-materializes is left to the imagination. I don't think we'll have seen the last of him though. I hope we haven't. This episode has made him a lot more interesting. Also, Christopher Heyerdahl is a great actor, those last scenes were half way to heartbreaking.
Last episode, by the way, when Magnus referred to "the departure of John", that seemed a little strange. After all, the guy can teleport to any destination on the planet in a second, he can't ever really be that far away. And this week Helen called him for help, and there he was. I wonder if those two episodes were supposed to be shown the other way around. It would be weird, but it would make that line make a lot more sense.
Edit: - Nope, apparently not. Amanda Tapping says here that Sleepers was supposed to be much earlier in the season but they couldn't get Jonathon Young then.
Either way, Magnus and Tesla really are the last of the Five, and if Tesla is mortal now (Helen said he was, but I don't know if they've actually proved it, especially since he clearly does still have an ability) then sooner or later it's going to just be Magnus. Harsh. She's lost a lot of people this past season. Of course, I'm fairly sure Druitt will be back and Tesla will either find a way to re-vamp himself (preferably) or still be around for a long time anyway.
No Tesla this week though. After what happened last episode, I'm not surprised, I would expect him to want to get away somewhere on his own to lick his metaphorical wounds and study his new magnetic ability.
So is the double ep finale airing both episodes on the same day? That's exciting.