Doesn't make sense

I'm a huge fan of the Metroid games, I used to play the original on the old NES before there even were any sequels. Metroid Fusion isn't too bad, it's fun to play, and retains some Metroid feel, but when one really thinks about it, it really doesn't make any sense. The others did, the worlds were set up in an odd way where only special abilities could access other areas. That made sense though, because the Chozo that build the worlds were the ones that designed all the equipment to explore them. So it would make sense.
However, in MF, think about it, how in the WORLD did the scientists get around that space station!?

"Boss says he wants you to head on down to the research lab."
"Where is that again?"
"Oh, it's in sector 2. You need to remove part of the wall, crawl through a small twisting tunnel, shoot the door you come to with your pistol, and then climb up through a crack in the ceiling. You can't miss it."

Lastly, which of the crazy scientists went all around the station hiding missile packs, power bombs, and energy tanks? The weapons and armor made sense because they were being downloaded or had been acquired from an X virus, but who hid all the little power-up Chozo relics all around a space station?

It all made sense in the first games, but common sense seemed to be thrown out the window here for a change in story.