If you have a little extra carpet and wood, try a few demo cuts...
I did this trying to get the inside of my hatch to fit right.
From my eye... I see you may want to try a "Y" cut.
Again, just go a bit short of right to the wood... then pull the center flap toward the inner "bottom" of the "U", then pull the remaining flaps, left and right towards the inside.
maybe?