Nothing is known about the test subject before the outbreak.
At some point after the outbreak, he was infected and became part of The Pack. He volunteered, along with another test subject, to test The Machine in an attempt to enhance their powers. However, the test failed horrifically. The Machine shorted out and sent jolts of electricity through both test subjects, and the female test subject was disconnected and escorted to the infirmary. The male test subject was not so lucky, and a fire sparked inside his body, cooking him from the inside out. After the male test subject's death, Jack simply pushed the corpse out the window, and it landed many stories down.
Jack ordered Mark to test The Machine on the two test subjects, but it malfunctioned, cooking the male test subject from the inside out.