Trooper Tonkin was a Dendarii Free Mercenary Fleet soldier who accompanied Medic Norwood during the battle on Jackson's Whole against House Bharaputra. He and Norwood had the task of bringing Miles Vorkosigan's cryochamber to the fleet, but when they were trapped behind enemy lines, Norwood took advantage of another means of getting the cryochamber out of the battle. Unfortunately, Norwood was killed before he could tell Tonkin or anyone else what he'd done. Tonkin was able to give some aid in figuring out the mystery.