(coexisting on another dimensional plane)
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He was used later as a bargaining chip by Captain Maddox when the captain was attempting to force Lorca into naming his sister, who been killed by Lorca. When that did not work, Maddox poisoned Barlow with the DNA of the Comtaxan parasite. Barlow was brutally vaporized by the poison. (DIS: "Vaulting Ambition")