Ian Rapaport on NFLN just alluded to Sunday saying Tua didn't go through concussion protocol because it was determined to be a neck injury and not a head injury. Now, that makes more sense than clearing it at halftime.
As for the Bengal, what do you want him to do? Can't hit em high, can't hit em low, can't drive em down, can't land on em. That was basically a perfect rugby form tackle, hands around the waist and take to the ground. A severe injury on something like that means NFL QB might be beyond your physical capability.