He discovers the cause to be the energy-dependent Rutan spy, who kills Robar and adopts his human form. It then kills a Sontaran trooper sent to find Robar, and attempts to escape in the Sontarans' assault craft, but Lieutenant Vorn discovers the disguised Rutan and fires at it, injuring the Rutan and forcing it to retreat.
He determines the culprit to be the energy-dependent Rutan spy, who kills Robar and takes on his human appearance. It then dispatches a Sontaran soldier sent to find Robar, and tries to escape in the Sontarans' assault vessel, but Lieutenant Vorn discovers the disguised Rutan and shoots at it, wounding the Rutan and forcing it to flee.