The Scene in Supermarket Makes No Sense?!?!

They are in an abandoned supermarket next thing you know they are in an unloading dock with countless other junkies. This scene made no sense to me. what an unorganized and ridiculous way to sell heroin to a bunch of junkies. Then they start shooting and running away to music. This whole movie has loads of funny parts that were not meant to be funny and this is one of them. Felt like it was written by a 10 year old lol. It was an epic movie tho i watch it every year or two