So the Doctor and Harriet are so very much in sync that it almost sells this whole crappy bit, and if you "recombine" calcium with a "compression field," you can use "acetic acid," or "vinegar," just like Hannibal. There's a lot of "Of course!" and "You got it!" between Harriet and the Doctor, a bad trick on the best of days, but one that Davies uses overmuch anyhow. It gives the illusion of cohesion, like you'd feel stupid if you didn't "get it" the way the Doctor and Harriet do, like whenever somebody writes something, a poem or something, on a TV show, and the characters talk about how well-written it was. And then you remember that it was written in reality by the same person making the characters say that, and it's gross. So whatever, Jackie and Mickey go through Mickey's kitchen looking for stuff with vinegar in it. There's a cute point where Rose knows from memory where Mickey's vinegar is, even though he doesn't, that rings very true and sweet. And the Slitheen is still coming. "Gherkins! Yeah! Pickled onions! Picked eggs!" And in the Cabinet Room, the Doctor's like, "You kiss this man?" The Slitheen FINALLY kicks the door down -- now that they've got all their ingredients together -- and they throw vinegar at it, and it explodes, covering Mickey and Jackie with green stuff. On the other end, they sigh with relief and drink some brandy, and Rose asks an Excellent Question which Harriet answers: "Hannibal crossed the Alps by dissolving boulders with vinegar." So you can see how that was a good shorthand between Harriet and the Doctor for what happened next: you say "Hannibal," I think "exploding living calcium by throwing brine and gherkins." "You got it!" "Of course! it's brilliant!" Fuck off.
Asquith and Green can feel Sip Fel Fotch Pasameer-Day Slitheen die, and Asquith shrugs that someone must've gotten lucky. "That's the last piece of luck anyone on this rock will ever have," says PM Green, and they head out to face the nation. "Ladies and Gentlemen...Nations of the World...Humankind. The greatest experts in extra-terrestrial events came here tonight. They gathered in the common cause. But the news I bring you now is grave indeed."
Mickey, toweling off bits of Sip Fel Fotch, comes into the room to watch the acting PM. "The experts are dead. Murdered, right in front of me, by alien hands. Peoples of the Earth, heed my words. These visitors do not come in peace." Mickey takes the phone from Jackie and holds it toward the television, telling the Doctor to listen. "Our inspectors have searched the sky above our heads and they have found massive weapons of destruction, capable of being deployed within forty-five seconds. Our technicians can baffle the alien probes, but not for long. We are facing extinction -- unless we strike first. The United Kingdom stands directly beneath the belly of the mothership. I beg the United Nations -- pass an emergency resolution. Give us the access codes! A nuclear strike at the heart of the ship is our only chance of survival. Because -- from this moment on -- it is my solemn duty to inform you. Planet Earth is at war." Sigh. Got it. It's sweet, really, and it's quite earnest, but there's a difference between relevance and weak parallels to current events. You're not lending yourself any gravity with this kind of thing, show. The Doctor is simply flabbergasted that the people would honestly believe the PM telling them about this imaginary threat ("They did last time," says Rose, which: valid), and the Doctor realizes that the Big Ben piece of the mystery -- they went for the huge scary invasion spectacle because when humans are scared, they lash out. Harriet asks an Excellent Question, but the Doctor goes to the metal blast doors and opens them -- and the Slitheen are still standing there. WHY?