Yes.

"All electrons would fall into their ground state. Chemistry would be impossible."

Yes. But you may not care...

"Molecules would collapse. Atoms would fall into each other, releasing immense quantities of binding energy."

You'd end up with a super dense substance, wouldn't you? Completely non-reactive, chemically. And almost unbreachable, given the huge energies required to detach non-Pauli atoms.

Ideal hull material, Irina...

"But it's all impossible," Larionova said weakly. "You can't violate Pauli."

Of course you can't, Dolores Wu replied.

Inside an opaqued bubble-shelter, Larionova, Dixon and Scholes sat on fold-out chairs, cradling coffees.

"If your mercuric was so smart," Larionova said to Dixon, "how come he got himself stuck in the ice?"

Dixon shrugged. "In fact it goes deeper than that. It looked to us as if the mercuric burrowed his way up into the ice, deliberately. What kind of evolutionary advantage could there be in behavior like that? The mercuric was certain to be killed."

"Yes," Larionova said. She massaged her temples, thinking about the mercuric's infection. "But maybe that thread-parasite had something to do with it. I mean, some parasites change the way their hosts behave."

Scholes tapped at a data desk; text and images, reflected from the desk, flickered over his face. "That's true. There are parasites which transfer themselves from one host to another -- by forcing a primary host to get itself eaten by the second."

Dixon's wide face crumpled. "Lethe. That's disgusting."

"The lancet fluke," Scholes read slowly, "is a parasite of some species of ant. The fluke can make its host climb to the top of a grass stem and then lock onto the stem with its mandibles -- and wait until it's swallowed by a grazing sheep. Then the fluke can go on to infest the sheep in turn."

"Okay," Dixon said. "But why would a parasite force its mercuric host to burrow up into the ice of a frozen ocean? When the host dies, the parasite dies, too. It doesn't make sense."

"There's a lot about this that doesn't make sense," Larionova said. "Like, the whole question of the existence of life in the cavities in the first place. There's no light down there. How do the mercurics survive, under two miles of ice?"

Scholes folded one leg on top of the other and scratched his ankle. "I've been going through the data desks." He grimaced, self-deprecating. "A crash course in exotic biology. You want my theory?"

"Go ahead."

"The thermal vents -- which cause the cavities in the first place. The vents are the key. I think the bottom of the Chao ice-cap is like the mid-Atlantic ridge, back on Earth.

"The deep sea, a mile down, is a desert; by the time any particle of food has drifted down from the richer waters above it's passed through so many guts that its energy content is exhausted.

"But along the Ridge, where tectonic plates are colliding, you have hydrothermal vents -- just as at the bottom of Chao. And the heat from the Atlantic vents supports life: in little colonies, strung out along the mid-Atlantic Ridge. The vents form superheated fountains, smoking with deep-crust minerals which life can exploit: sulphides of copper, zinc, lead and iron, for instance. And there are very steep temperature differences, and so there are high energy gradients -- another prerequisite for life."