Clutching the cherry red fire extinguisher to her chest, Donna edged through the doorway into a workshop off the main hangar, hoping to find the Doctor and ready to blast any slimy grey aliens in her way. Who’d’ve thought they’d be vulnerable to such a common object?
“Carbon dioxide, Donna! Good ol’ See-Oh-Two,” the Doctor had exclaimed, grabbing the canister from its sconce beside the tool cabinet on the main production floor and tossing it to her. “Harmless to us, but poison to the Kolzaks.”
“Can’t be!” she protested as she pulled the pin on the handle and hefted it up. “That stuff’s all around us. They shoulda keeled over the moment they landed.”
“Nah,” he growled, dismissing her with a flick of his hand as he dashed over to another extinguisher. Inspecting its label, he shook his head and turned back. “Atmospheric concentration’s too low. Probably tickles but not much more. Now, that,” and he wiggled a finger at her makeshift weapon, “that’ll sting something fierce.”
Donna had to agree. When a Kolzak had grabbed her and hauled her off to ask the usual “Who are you? What are you doing here?” questions, it had cringed in pain at her shouts in its face, and she’d taken the opportunity to make her escape. Her mum always said that her voice was a lethal weapon, but hadn’t meant it quite like this.
She crossed over to the cluttered workbench to check for alien devices, then jumped and whirled as the door on the opposite side of the room banged open.
“Ah, Donna, there you are!” The Doctor swept in, hands buried deep in his blue pinstriped pockets. “Still locked and loaded, I see.” He ducked to peer out of the grimy window, then flashed a grin back at her. “I found their base of operations. Let’s shut ’em down. This way.” He strode across the room to her, then jerked his head toward the main hangar. “Come on.”
Hesitating, she looked up at him with pursed, worried lips. “Doctor?”
“What is it, Donna?”
She winced a little at his sharp tone. “We’re mates, yeah?” she murmured.
His expression softened as he gazed at her. “Best mates, Donna,” he declared, his smile brilliant. “To the end.”
“Just checkin’.” Lifting the canister, she squeezed the handle and hit him full in the face with a long burst of gas. Shrieking in agony, the Doctor curled in on himself, his clothes and hair dissolving into his skin, colours fading to unctuous mottled grey. It batted feebly about its head with thick, clay-like hands and its mockery of a human face glared at her as its features melted away, its watery black eyes filled with malice and fear.
“Shift!” she yelled, brandishing the extinguisher, and it spun and scuttled away. “That’s right. Go on. Serves you right, thinkin’ I couldn’t tell. You’re the spittin’ image of him, but those eyes… You can’t copy the Doctor’s eyes. Not with all that evil and hatred in your heart. Not in a million years of tryin’.”
Straightening up, she pulled the extinguisher’s nozzle up and blew across it with the pride of a job well done. “Thinkin’ you can fool me. Ha!” With that, she crept back into the hangar to search for her real best mate.