Understanding the Plain

So the milkman said to himself, "In what capacity do the pelicans need it?" He thought about this for a moment while awkwardly fumbling with his new black bird cage. It smelled slightly of cedar, maybe with a hint of varnish, catching the back of his throat. Where had this thought come from? He couldn't remember.
Standing in the long, gloomy hallway, he felt like a car in a scrapyard; mainly intact, but with scratched panels and cracks in the windows. Once again he thought of pelicans for a moment, before marching towards the nearest door, which was a reliable distance away. It may have been sixty feet, one hundred yards, or even a mile, yet his curt footsteps maintained their audacity, rhythmically pumping the corkboard floor.
The door was misshapen, as though a human jelly trifle had melted away the edges when entering. Somehow the door fit, even with its wobbly edges. "That surely can't be deepest oak," the milkman thought aloud, although no one was there to listen, and even if they were, they wouldn't have. He wrapped a gnarled knuckle on the rippled door and waited patiently. No sound emanated from within, so he tried again, with added fervour. Still nothing. He waited. His smile faded to a frown beneath his mushroom cloud eyebrows.
The black bird cage in his middle hand vibrated, much to his annoyance. Tutting and grumbling he placed it on the cork, before returning his attention to the door. In the failing light, the door looked almost embedded in the wall, as though part of some abstract wallpaper pattern. His veined fist pounded on the wood five times. He thought he heard someone stir within, or perhaps it was the damn bird cage again. A moment fleeted passed like a drunken snail. Yes, it was just the blasted bird cage. A rage began to flare up inside the old young man and he thrust his pink arm through the door. He should have been surprised at the ease in which this act happened, but instead he focused on the dark ooze pulsing from within his flesh. A sight most people would be disgusted at, the milkman merely smiled, as though slicing his forearm open was intended.
The door was tugged open from inside, momentarily knocking the milkman off balance as it pulled him forward. Once his eyes adjusted to the hazy gloom, he saw the owner of the house with the wibbly wobbly door; it was a dog, coloured magnolia, with a red tail. It was standing on its hind legs, and seemed fairly nimble. For a magnolia walking dog. The dog rolled its eyes after inspecting the bloodied hole in its door, and skipped across to the adjacent wall, where it flicked a switch. The lights spluttered into life and made the milkman shield his eyes.
"Look what you did to my door!" the dog lamented, with a softer voice than one would expect.
The milkman's smile returned as he realised what was happening. "It's the bird cage," he thought. His grin remained and widened, bearing his stained traintrack teeth. The walls were a dirty brown colour and the room smelled vaguely of vinegar and weather. Each wall had a portrait of an ornithological creature in distorted positions. In fact, he could swear each bird was a pelican.