They are easy to get out except you need two hands to hold the cube steady while you pull on the arrow with one hand.
Genetic mutation is helpful.
You can put a leg up against one edge while holding the other edge with one hand and use the last hand to pull out he arrow. Remember that the blades are sharp so move your leg out of the way before you cut it. They really bury up deep even at 60-80 yards so you have to pull a long way.
I think the foam is too soft compared to a deer hide with hair to activate them to open. But it does make you worry.