... there is one.
A very uneven episode otherwise, but it's not often that Deus Ex Machina is more than just a way of resolving a plot withing 45 minutes.
I am no fan of the Slitheen, but in "Boom Town", the one remaining member of the family was a bit more effective than the ones that we say in "Aliens of London"/"World War 3".
Also, I don't think they're quite as naff as they've been made out to be in the fan community. Doctor Who caters to the general public, not just the rabid fans, and if, as I read somewhere, kids in British schoolyards are playing Slitheen by pretending to zip their heads open, then that's mission accomplished as far as the producers are concerned.
One Slitheen, like one Dalek, is more interesting, though, than a whole pack of them, and "Margaret Blaine" got some good psychology in. Like the Dalek, she got to argue her side of the story, painting the Doctor as no better than her. Unlike the Dalek, she remained a deceptive manipulator right until the end. Then again, as the trailer for next week indicates, maybe that was also true for the Dalek. I do fear that next week's episode will turn out to be a bit rubbish. It looks like all the speculation about "Anne Droid" and the Reality TV stuff was true, which could make for a very naff 45 minutes, Daleks or no Daleks. Or maybe not.
But oh, for that God in the Machine. Don't worship it, you'd never get a day off.