This is an escape-from-space-Alcatraz episode, but surprisingly not a ripoff of the excellent escape-from-Earth-Alcatraz movie The Rock, which wouldn’t come out until 1996. In true Space Precinct fashion, it’s got one really good subplot and a whole lot of WTF, and a couple of surprising guest stars.
On with the story. There’s a Creon crime boss who’s due to be shipped out to a prison asteroid known as The Rock, along with an escape artist with the tedious nickname of Houdini. Creon crime boss falls ill, so Castle and Took, who were supposed to be doing the driving, have to take him to the hospital and Brogan and Haldane are pulled off leave to drive Houdini. However, Brogan is so sad that he’ll be missing watching the World Series game with Haldane and his kids that Castle and Fredo, the other Tarn officer, fiddle the schedules, so it’s Castle and Haldane taking Houdini to the Rock.
WTF 1: why not just keep Houdini on ice until the Creon’s fit to travel?
However, the Creon’s henchman, Volker, played by Stephen Greif sporting an unexpected American accent, has (of course) staged a take-over of the Rock, by spreading a virus which kills the guards and the surviving prisoners. Castle’s got a cold which turns out to give her immunity to the virus, so (of course) she’s also got to snog Haldane to give him immunity. If there was the tiniest bit of chemistry between those two it might actually work sometime.

WTF number two: Haldane and Castle turn up with Houdini and innocently hand him over to one of the escapees disguised as a guard… and then Volker appears with a gun and takes them hostage. Why? Why not just let them tootle back to headquarters none the wiser?
We then get to the good subplot, which is that Houdini delightfully plays the police and the criminals off against each other, convincing both of them he’s on their side, until he’s got what he wants– which is the police cruiser, allowing him to escape with impunity.
On Earth, Tookie is having a bad feeling that something’s wrong with Castle, because Tarn have emotional connections to people they care about, and in a normal police series there’d be a lesbian subtext between those two, but alas, one of them is wooden as a plank and the other is swathed in ten pounds of latex and animatronics.
Anyway, the cops figure out something is wrong when the police cruiser turns up without the police. Chief Podly impersonates the Creon criminal so as to sneak a force into The Rock and re-take it (that’s WTF number 3, but at this point who’s counting). Brogan reveals he tape-recorded the World Series game so he can watch it with Haldane, and everyone’s happy, sort of I guess.
The other guest star this episode is some young guy named Ray Winstone, who probably will never amount to much.