Part 15 (1/2)

'It is you ape-primitives who are mad,' said Icthar. 'You have developed this weaponry. We cannot be held responsible for it.'

'Contact the heads of governments,' urged Vorshak.

'Make your demands, tell them you want a share of the Earth. They'll listen.'

'Your race has had its chance,' said Icthar implacably.

'Please, try one more time, for pity's sake.'

'It is too late for pity,' said Icthar. 'It is much too late.'

In the chemical store the pump was humming steadily, feeding Hexachromite gas into the ventilation system.

The Doctor said thoughtfully, 'Of course, it will take some time for the gas to spread.'

'Will it work fast enough?' asked Tegan anxiously. 'How long before it floods the whole Base?'

'I rather hope that won't be necessary. If I can get back to the Bridge, I may still be able to reason with Icthar, persuade him to abandon the missile launch.'

Turlough looked at him in amazement. 'You're mad, Doctor. You've tried that once already, remember?'

'Ah, but this time I'll have a counter-threat to back up my arguments,' said the Doctor, hopeful as ever.

Icthar studied the flow of data across the screen. He looked almost pityingly at Vorshak. 'Soon it will be all over.'

Vorshak stared at him in silent anguish, poised to make a last-minute attack.

Suddenly Tarpok called, 'There is computer resistance to the Manipulator.'

Hope flared up in Vorshak. 'I told you you'd never succeed!'

'Increase the power, Tarpok,' said Icthar placidly. 'It seems that your computers are as stubborn as you humans, Commander. But do not be deceived. We shall overcome you both in the end.'

The Doctor stood watching sadly as the pump drove the deadly gas into the ventilation system. 'Right, that's it, I want the rest of you to go back to the TARDIS and wait for me. You left the door ajar, Lieutenant Preston?'

She nodded.

The Doctor went on, 'You'll be safe inside the TARDIS whatever happens.'

The siren rang out again, this time with a different note.

'They've changed to yellow alert,' said Bulic.

The Doctor nodded. 'We must go.' He looked round the little group. 'Good luck, all of you. I'll join you in the TARDIS as soon as I can. If I don't Tegan and Turlough will have to do the best they can.'

They heard a voice behind them. 'So Doctor, I have found you!'

They turned.

Sauvix, leader of the Sea Devils was standing in the doorway.

12.

Sacrifice On the Bridge all eyes were fixed on the read-out screen, on the flas.h.i.+ng words 'YELLOW ALERT'. Incongruously the Intercom beeped.

Icthar touched a control. 'Speak!'

They heard Sauvix's voice. 'I have the Doctor, Icthar.'

'And you have your orders,' said Icthar implacably. Kill him.' He turned back to the screen.

'Sauvix, you must listen to me,' pleaded the Doctor.

There was a gleam of what might have been amus.e.m.e.nt in the great bulbous eyes. 'No, Doctor. You must die. But first, switch off that pump.'

As the Doctor moved towards the pump, Lieutenant Preston looked swiftly around her.

Turlough had laid his blaster-rifle on top of one of the cylinders. It wasn't all that far from her...

As Sauvix's weapon moved to cover the Doctor, she made a desperate lunge for the blaster. She s.n.a.t.c.hed it up, aimed...

Sauvix whirled round and shot her down.

As Preston died, her hand tightened on the trigger of the blaster. It fired, burning a hole in a cylinder close to Sauvix's head.

The gas spurted out. Sauvix reeled, clutching his gills, and fell dying to the floor.

Tegan was kneeling by Lieutenant Preston's body.

'She's dead, Doctor.'

The Doctor nodded sadly. 'Such a waste.'

'She saved your life,' said Tegan. 'Don't let her sacrifice it for nothing.'

'I won't. I must get to the Bridge!'

'You'll need some help. We'll come with you, won't we Turlough?'

Turlough nodded resignedly. As far as he could see, anywhere on the Base was just about as dangerous as anywhere else.

'All right,' said the Doctor. 'Bring some of those oxygen packs. We may need them.' He pointed to a wall-rack which held oxygen cylinders with attached face-masks presumably some kind of rescue kit.

Turlough and Tegan took an oxygen pack each.