The Tranquilizer Pistol is a temporary weapon seen and wielded by Michael Thorton during his initial stay in the Graybox. The weapon is wielded by the Graybox guards upon Thorton's awakening and his initial test to determine his reaction under presssure. One is then obtained by Thorton himself as he proceeds with his "escape." It is designed to only fire specialized "tranquilizer" rounds, for the purposes of non-lethal takedowns and captures. This model appears to be based on a Sears, Robuck, and Co. Ted Williams Match Pistol, CO2 powered and designed to shoot darts.
This weapon is only usable by players during the beginning portions of the first mission, taken from a tabletop in the room outside of the medical bay where Thorton awakens. From there, it can be used against any of the soldiers guarding the facility instructed to stop and recapture Thorton by Alpha Protocol as a part of the test. The player can then reobtain this pistol once again during Mina Tang's Bonus Challenge during the Weapons Orientation Test.
A specialized, gas-powered pistol with clip-fed tranquilizer ammunition. Intended for live capture, the sub-sonic rounds will deliver a nasty concussive wound on impact and follow with a quick-acting dose of debilitating pain killers.