U.S. Magistrate Judge Sally Shushan apparently kicked out of court an engineer who switched sides from BP to Halliburton in Deepwater Horizon litigation, but her exact action and her reasons remain secret. On Dec. 8, she signed and sealed an order on a motion to disqualify Michael Viator as an expert in computer modeling of the rig explosion and the oil spill that followed. Viator quit Halliburton in March and joined BP consultant CSI Technologies. Shushan's order must have favored Halliburton, because BP moved four days later to designate a substitute expert. The motion compounded the mystery, for Shushan sealed it at BP's request. BP objected to Shushan's order on Dec. 13, and asked U.S. District Judge Carl Barbier to overturn it.