Realising that the Doctor was right all along, Grover orders the reluctant Sternberg to surrender the vials, but just as they are handed over the Semquess tanks arrive. As Brokk still holds Nancy hostage, the UNIT troops are forced to fight off the Semquess while Brokk escapes, but the Semquess mothership then emerges from the lagoon, and Brokk realises that he will never escape them. Following him at a distance, the others see him place Nancy down and continue on to the ship alone. Realising what is about to happen, the Doctor sends Grover's group back to their ship and tells the UNIT team to assemble on the beach. Benton has left one man standing by the time bridge, and the Doctor has Yates radio instructions to him to pass on to the Brigadier. Brokk's ship takes off, but the Semquess shoot it down, and its fragments are scattered across the island—thus covering the island in omicron radiation and enabling the Brigadier to pilot the time bridge to the beach. As the UNIT team escape and the repaired Constitution heads back out to sea, the nuclear core of Brokk's ship plunges into the heart of the volcano, triggering an eruption which destroys Salutua and scatters the fragments of Brokk's ship throughout the surrounding area. One day, one of these fragments will be found and eaten by a shark.