At some point prior to the loss of authority on Sevastopol, Chief and a team of engineers were working on maintenance in the reactor level, attempting to correct a series of intermittent brownouts. While working, one of Chief's team vanished without a trace, the only possible exit route being the air vent. Though unnerved, Chief intended to continue working and report the incident to the Colonial Marshals. Amanda Ripley would later discover his body and the bolt gun, which she would use for the rest of her time on Sevastopol.