"Such a massive deviation from SOP and foray into such an unknown area"
Unknown? DHC-100 with 12000 feet of runway? Maybe unknown for someone who so blindly leans on the concept of SOP (which is not even applicable in this case) that they don't dare to use their own judgement.
If you are 100 % sure that you can stop but only 80 % sure the aircraft will fly, which is the best decision?