"One more time," said the woman in the brown leather jacket. She pushed the Up elevator button on the lobby wall while the man in the boiler suit pressed his hand against the doors of the leftmost elevator. This time the doors cracked open a little. The man pulled at one door with both hands, while the woman ran the few steps to join him and pull at the other door. They forced the doors a few handwidths apart, then the woman pulled another glowing ball out of her pocket, just as the depths of the elevator shaft started to glow on their own. The woman tossed the glowing ball into the shaft. A sound like a thousand tiny screams rose and pitched before fading into the higher frequencies, then the white light of the ball and the shaft faded after it.
The man and the woman let go of the doors, and the man carefully forced them shut again.
"One down, two more to go," said the woman.
"What the hell is that supposed to do?" The man and the woman turned to find that a young man had just come in the rear lobby entrance, and had been watching them.
"Dust mite exterminators," said the man.
The young man jerked his head towards the woman. "How come she's not in uniform but you are?"
"I'm a consultant," said the woman.
"Dust mite exterminations have to be carried out in all elevator and garbage chutes in buildings over three stories," said the man in the boiler suit. "New City of Toronto regulation. Once every five years."
The young man frowned. "Is this going to make my rent go up?"
"Not at all," said the woman. "It's a pilot project right now. I'm here to help and observe, and... then in a few months I'll come back and check on the efficacy of the... treatment."
"That stuff's not bad for pets or anything, is it? I keep canaries and my girlfriend's got a rabbit."
"Oh no," said the woman. "It doesn't use chemicals. The light causes a static discharge, and the static electricity kills the mites. It's very environmentally-friendly, and it doesn't work on any animal much larger than a dust mite."
"Friend of mine is majoring in chemical engineering," the young man said. "I'm gonna ask him about it."
"It's a very new process," said the woman. "Don't be surprised if your friend hasn't heard of it. Actually, if you have any friends who are electrical engineers or physicists, you might be better off talking to them."
The young man scowled, muttered a thank-you, and left through the front doors.
The man in the boiler suit pulled a handkerchief out of his breast pocket and made a show of wiping his hands as the front doors closed and the young man walked out of earshot. "Did you have to tack on that last bit?" he said.
The woman shrugged. "I'd be surprised if even the student of chemical engineering is real," she said. "Did you see his coat? Sixty years on this planet, and I'm telling you that has to be a fine arts major."
The man in the boiler suit grunted. "So much for disinterested research."
"There's nothing non-disinterested about inferring from previous observations. Come on, let's get the rest of this lot over with."
They had trouble with the doors of the second elevator, but the third one went smoothly. In both cases the hostiles simply screamed their way into oblivion, with no counter-attacks or attempts at defence.
The man in the boiler suit pushed the last set of doors closed, checking that no other tenants had entered the lobby. "That seemed a little too easy."
The woman nodded. "Even if they're just starting an infestation, it's surprising that there's only the two sites and no backup," she said. "The ones at the subway station had formed parasitic relationships with local hosts. Here they haven't even bothered to do that."
"So what now?" said the man in the boiler suit.
"It's safe to take the elevators now," said the woman. "We go to the top floor, drop some light grenades, then figure out the garbage chute layout and go to the next collection floor and drop some more."
"Do you have enough grenades with you?"
"We could do two buildings this size and I'd still have leftovers. Not to worry."
The man hit the elevator Up button. "Might as well get going."