The canister in Jennifer's room.
The first man opened the air conditioning vent and placed a small metal canister with a trigger mechanism inside the duct. The canister looked like a large hairspray bottle from the 60s. Attached to it were a light sensor and a small radio transmitter with a battery.
He whispered in an ancient, indigenous language. “I’m activating this thing. Turn off all the lights. We don’t want this going off too early.”
She stood and turned on the light in the bathroom. It wasn’t very bright, but it lit up the bedroom and some of the light also fell on the air conditioning vent. The room felt hot. For some reason the air conditioning wasn’t cooling too well. She cranked it up to maximum, using the digital dial on the wall.
The cold air came rushing in and created thin vapors at the exhaust vent. Hidden deep inside the air conditioning vent sat the small metallic container. The light triggered a simple photocell and a clear mist sprayed from the pressurized metal container. At the same time, the radio transmitters sent a signal to a group of very anxious men not far away. They had cursed that Jennifer had brought a man to her room, but they’d waited patiently. Now they’d only have to wait another half hour and everyone in the room would be deeply sedated.
From Killer Drug, by Peter Rost.