Just another day

Two men sprinted side by side.
"What do they want?" the Doctor asked.
"They demand everything."
The Doctor looked back, letting his experienced legs avoid obstacles. The aliens' seemed deadly, but those were just first expressions.
"Have you tried saying no?"
"Not really," the man answered.
They turned to face the creatures.
"We demand...," the two aliens started together.
"No!" The man said firmly.
The creatures leaned back, confused. They conversed in high-pitched squeeks.
Then, they turned to the two men, who barely dodged their weapons.
"Time for plan B," the Doctor thought. "And to prepare plans C to F."