Russel wasn't a hero, and he knew it.
So he wasn't a hero. He wasn't an idiot with more courage than brains who charged into danger when he thought someone needed help. He wasn't a white knight, and even if he was Edward Elric definitely wasn't a princess who needed rescuing. And if he met a homunculus and got on its bad side, he'd be so much bloody meat before he even had a chance to consider fighting back. His mind reminded him of all this almost constantly as he traveled down into the underground city.
But Ed had been gone for two days even though that girl, Rose, had come fleeing up and away so quickly that he and Fletcher hadn't even had a chance to catch her attention and find out what had happened, Russel was about the only person who even knew where he /was/, and, even with the Fuhrer apparently dead, he frankly felt better about sneaking through a dead city than he did at the thought of returning to the military headquarters and trying to find help there. At least there were a lot less homunculi than military members, hiding away in a much larger place, which meant that it would be a lot easier to hide if anybody spotted him and decided that he'd look better dead.
Luckily it was easy enough to figure out the path Ed had taken. Dust and grime had had hundreds of years to build up in the hidden city, and it didn't matter that Russel would usually consider himself an awful tracker with marks as clear as the ones Ed had left here and in the filth.
In fact, it was so easy that he was just starting to think he should turn tail and run because everything in him was screaming that it couldn't possibly be that easy, that such a clear path had to be a trap, and that he wasn't a hero so why would should matter if he acted unheroic, when he walked around a corner and straight into the remains of a bloodbath.
There were no bodies to be seen, but blood... it was splashed all over the place, including a stain so large that he wasn't sure how anybody could have survived losing it all to drag themselves away. And in the center of the area, in the middle of a burnt out transmutation circle, was...
"Ed!" He ran out from the piece of rubble he was hiding behind, completely forgetting to worry about any threats at the sight of the naked young man lying curled into a ball with his back to him. He was so caught up in searching the body for wounds with his eyes as he ran towards it that he entirely missed the things that weren't exactly right: the hair that was too short and a little too dark, the lack of a scar on the shoulder the other young man was lying on, the leg that was actually a /leg/. It wasn't until Russel reached him and jerked him onto his back to check for a heartbeat that if finally all sunk in at the sight of the much-too-young face.
"Al?" he asked himself, disbelieving. He was sure that Al was supposed to be older than this, the resemblance was impossible to deny. Maybe being a undersized little bean just ran in the family. When he realized that yes, Al was breathing, yes, his heart was beating, he began to shake him. "Al, hey! Wake up!"
Slowly Al's eyes opened, and he blinked up at Russel with an expression of sleepy confusion. "Who'sit?" he mumbled muzzily.
Russel laughed a sharp bark of relief, and moved to slide his arms under Al's shoulders and knees to lift him up. He couldn't help wishing that he'd taken meeting Ed as an opportunity to perfect his impression so that he'd have a big red coat of his own to wrap Al up in and give him some cover before they went back up to the populated world, but just getting there was a lot more important than worrying about propriety. "It's Russel, remember? Fletcher's waiting back up above the ground. Don't worry, Al, I'll get you out of her in no time." And once that was taken care of, they could start trying to work out what the hell had happened to Ed.
He didn't even realize until much later that Al hadn't shown any sign of recognition at his name.