Finally Nirgal showed up, gliding through the crowd like Mercury on an urgent errand, smiling hugely and greeting acquaintance after acquaintance, people who wanted to hug him or shake his hand or just touch him. “I’m going to cut the tent wall now,” Nadia told him. “Everyone has masks, and we need to get out of here faster than the gates will let us.”

“Good idea,” he said. “Let me just announce what’s happening.”

And he jumped three meters into the air, grabbing a coping on the gate’s concrete arch and hauling himself up so that he was balanced on it, both feet on the same three-centimeter strip. He turned on a small shoulder loudspeaker he was wearing, and said, “Attention, please!— We’re going to start cutting the tent wall, right above the coping— there should be a breeze outward, not very strong— after that, people nearest the wall out first, of course— there will be no need to hurry at that point— we’ll cut extensively, and everyone should be out of the city in the following half hour. Be ready for the cold— it will be very invigorating. Please get your masks on, and check your seal, and the seal of the people around you.”

He looked down at Nadia, who had gotten a little laser welder out of her black backpack, and now showed it to Nirgal, holding it overhead so that much of the crowd could see it.

“Is everyone ready?” Nirgal asked over his loudspeaker. Everyone visible in the crowd had a white mask over their lower faces. “You look like bandits,” Nirgal told them, and laughed. “Okay!” he said, looking down at Nadia.

And she cut the tent.

• • •

Sensible survival behavior is almost as contagious as panic, and the evacuation was quick and orderly. Nadia cut about two hundred meters of tenting, right above the concrete coping, and the higher air pressure inside caused an outflowing wind that held the transparent layers of the tent fabric up and out from the coping, so that people could climb over the waist-high wall without having to deal with it. Others cut the tent near West and South gates, and in about the time it takes to empty a big stadium, the population of Burroughs was out of the city, and into the cold fresh air of an Isidis morning: pressure 350 millibars, temperature 261K°, or -12° Celsius.