2012 Rear Window Wiper Motor Cover

2012 4Runner Limited.
How in the sam hill do you get the plastic cover off the rear window windshield wiper motor?

I recently bought in immaculate 2012 4Runner limited with under 100,000 miles. The other day I noticed when I raise and lower the rear door, I can hear something rolling around in the plastic cover of the rear glass windshield wiper cover. It's almost like they left something behind in the cover when they assembled the 4Runner at the plant. It almost sounds like a socket or spacer rolling around in the cover.

I can't for the life of me figure out how to remove the cover.