"Look at these trees! They're so huge! Have you ever seen trees this big?" Donna asked Sherlock, who turned away from her with a 'humph' of derision and crossed his arms.
"Trees are boring."
"Boring?" Donna echoed, incredulous, "Trees provide everyone with clean air and you reckon they're boring?"
"Clean air, dirty air...what does it matter?" asked Sherlock, "We're still stuck here until the anomaly re-opens."
"Well it doesn't seem so bad," said Donna, looking around at their surroundings, "Nice and quiet, away from the stresses of modern life..."
"Quiet is boring," Sherlock growled, "The closest I'm going to get to a case out here is if you wander off and get eaten."
"Well, excuse me for being an optimist. Or is optimism too 'boring' for you, cheek-boy?"
Sherlock turned towards her, eyes wide, "What did you call me?"
"Oh, don't act all surprised. A man with a face like yours really ought to be used to the nicknames by now," Donna said, rolling her eyes.
Sherlock's face twitched and he turned away from Donna again, "I'm going to stand here and ignore you until the anomaly re-opens."
"Whatever, cheek-boy," Donna retorted, walking away from Sherlock and back towards some of the trees that she'd been admiring earlier. Suddenly, she tripped and fell face-first into the ground, letting out a yell of surprise. As she recovered she noticed that Sherlock hadn't even turned to see if she was okay. Donna glared at him as she stood and looked for whatever she had tripped over. It didn't take long for her to catch sight of the cylindrical black object lying ostentatiously on the ground.
"What is this?" she asked herself, picking the object up and carefully examining it, "Hey Sherlock, take a look at this," she called out to the sulking consulting detective. When he didn't make any sign of having heard her, Donna walked back over to him and held the object directly in front of his face until he gave in with a sigh of annoyance and elicited a response.
"I don't know," he growled.
"Well, hang on a moment, this looks like some sort of 'on' switch," said Donna, simultaneously pressing the aforementioned switch. Suddenly, a beam of light shot out of the far end of the object, which Donna dropped in shock.
"What the..." she began to exclaim, but was interrupted by Sherlock letting out an angry yell.
"LOOK AT THIS! JUST LOOK AT WHAT YOU'VE DONE!" he yelled.
"What?" asked Donna, looking up at Sherlock in puzzlement, but quickly seeing the problem and placing a hand over her mouth to keep herself from laughing too hard. One side of Sherlock's coat collar lay on the ground by the enraged detective's feet - having been sheared off by the powerful light beam - whilst the other half had remained stubbornly upright against his cheek. He was quite a sight.