This is where it got weird. Where one would expect a mashed face, a torn shoulder, a headlock even, to fell a guy, Drew kept chugging along, huffing and puffing away. He was powerful, strong, and even with his vision flashing in brief spurts of black and white, he attempted bringing in one more breath to help him through.
(Clarification; Super-Human Durability-Drew is able to withstand incredible amounts of punishment, pain, and can keep active beyond what a majority of most meta humans are able to withstand.)
There it was. Bigby flinched, just enough, with the pain, with everything else, the how slick his head, neck, and torso had become and the rapidly changing physiognomy of the would-be were-wolf, Drew would finally be able to tug, and tug, his chin bending down, and finally, pull free.
There was lancing pain across his shoulder. But it went mostly ignored, at this point, drugs and adrenaline, dopomine and hormones running through his blood at such a rate he could hardly feel how his muscles threatened to disappear into the ready abyss of his body.
(clarification; I think you got your sides mixed up. Drew is crushing the kidney with his right hand, meaning if you were to attack that arm, you'd go for the right shoulder. Furthermore. Severing muscles in the shoulder would not weaken the forearm and hand strength inherent to an attack of this sort.)
If he had, in fact, managed to pull out, there was a mighty tug, a pull, in his lower back, lifting Drew just enough to bring the left arm that had been pinned underneath of him, and slam it into Bigby's face/snout before he finally, graciously, went slipping into an unconscious stupor. He had to put the icing on the cake.
His nose, broken, his mouth a wreck and his teeth probably in need of a dental job of magnanimous proportions, a ruined shoulder senting blood and core everywhere, and a severe influx of blood to the brain took it out of a guy, it did.