Authors Note: I decided to take this in a slightly different way than I had intended, and am probably going to use an event from one of the episodes (can't remember which one) so keep in mind that ths ins't enritly original.
Disclaimer: Nope. FMA still doesn't belong to me
Hawkeye normally felt safe enough walking the dark streets with her faithful dog and reliable aim, but even she had difficulty beating off such a powerful opponent with so little warning. One minute she was glancing down at the trembling Hayate, the next moment she was thrown up against the wall by a huge force running into her. Going for her gun, she wheeled to face her attacker and was rammed again. Flipping her gun out, she fired several shots into the mass of her attacker, who then disappeared. Breathing heavily, Hawkeye strained for any sign of her attacker. The small whine from her dog was the only warning she had before her attacker dropped down on her from above. Hawkeye thrust her foot at the attacker's head (or where she thought it'd be) quickly firing several rounds, and hitting vital locations each time. Not a single bullet stopped, or even slowed, her attacker. With a gasp, she began retreating from her advancing attacker, before turning and running. Her head cracked as she hit the pavement, her opponent on top of her. She groped for her gun, but couldn't reach it and the edges of her vision were fading. She couldn't breath, couldn't see, couldn't move and fight- it was a nightmare. Was this how Mustang had disappeared, fighting this faceless and shapeless menace? The world fuzzed out, then refocused until it all faded to black and Hawkeye drifted away.
The release of pressure off her lungs, and Hayate's tongue on her face roused Hawkeye from her oxygen-starved unconsciousness. She lay, gasping, on the alleyway pavement for several minutes, gathering the strength to retrieve her guns and stand. She leaned against the wall, catching her self after stumbling over her bag, which had escaped the attack unscathed, the notes and files still intact. Her knees trembled and she collapsed, sliding down the wall to sit on the ground, hugging her knees and burying her face to stave off the lightheadedness and weakness leftover from her fight. Hayate crept over to her, whining and butting his head against her leg. She unwrapped her arms from her knees and reached over to hug her wonderful dog. "Thank you, Black Hayate" she croaked, "Don't worry. I'll be alright in a minute." She tried to stand and Hayate placed his paws on her thighs. "Alright, we can go." she rasped, "Just let me get my bag." Hoisting it up, the two limped their way home.
Hawkeye hobbled down the street, looking up in time to catch a glimpse of Mustang's house. Seeing a memento of her colonel reminded her of her realization, spurred by her invisible opponent's appearance. It may have been the same attacker. With renewed determination, she changed direction to return to the scene of the fight. But first she was going to grab a few supplies she had left in the care of the Colonel.
Hayate whimpered in fear as they approached the alleyway. Hawkeye produced a gun, but there was no sign of their assailant. The alleyway appeared completely empty. With great trepidation, Hawkeye and Hayate cautiously tracked the assailant's trail back to its layer.
The convoluted route the Lieutenant and her canine followed ended at an entrance leading underground; whether to a basement or the sewers she couldn't determine. Gazing down the stairs, past the locked gate, she saw a dark tunnel leading down into the black. Her unease grew exponentially. She couldn't beat off the one attacker with her gun, if her opponent had allies it would be suicide. Hawkeye backed up from the gate, preparing to find back additional support when she caught the distant strains of yelling and shouts of pain. She rushed back to the gate, listened for a moment, confirming the identity of the familiar voice, and shot off the lock of the gate, running down into the depths of the tunnel with her heart in her throat. She knew that voice. Mustang was near, and by the sounds of conflict, was in need of her support (or more accurately, her gun). His back, her job, and their dream was threatened, and she ran faster down the hallways until the light filtering underground increased, and she reached a horrifying sight. Rows of snakes, lizards, dogs, and demons, mutated almost beyond recognition, stretched out before her, blocking her way. Their growls rose as she appeared in their territory, and there was a moment of frozen shock, before the chimeras leapt. Desperately Hawkeye drew her machine gun and fired, filling the hallway with smoke, shots and blood.