Red is the color of blood. When a serial killer slashes your head in with an axe, it is the color of the liquid which fountains out of your head shortly before you die.
Blue is the color of your face when you get suffocated to death. After you hang yourself or get choked to death, your face becomes blue and you die.
Yellow is the color you see when you fall in an active volcano and your body gets fried and eventually cools down to become a part of igneous rock.
White is the color of pillows when you get smothered to death by one. Just as you're about to die, you see a brief glimpse of white before your vision fades to black for good.
Green is the color of the poison ivy that a murderer shoves down your throat which causes you to cough up blood and eventually die from the poison ivy. It is very painful.
Brown is the color you see when a weirdo ties you up and takes a big shit all over your face. Also, you may breathe some in and swallow a bit of it on accident.
Grey is the color you see when you're getting torn apart by a pack of wolves (or werewolves if there's a full moon outside) and eaten by them. Your bloody corpse will be left behind.
Pink is the color you see when someone forces you to watch "My Little Pony" until your brain turns into acid and melts out of your ears, eye sockets, nostrils, and mouth.
Orange is the color you see when you burn to death. Orange is the color of the fire which kills you (fire can be different colors but I already used blue, red, and yellow earlier so stfu).