Though this isn't a random injury out of nowhere which could happen to anybody. They had two, arguably three, concussions to consider which they ultimately dismiss. And, not to be too much of a b about it, but Tua isn't in the grade A list of QBs. You have a Mahomes or a Josh or perhaps, with his future potential, a Stroud, you maybe take the risk because of what they provide on the field of play. Tua doesn't quite have the talent to make it worthwhile yet, possibly because even the grade B list isn't that long, they took the gamble. But it seemed ridiculous and risky at the time. Now even more so.
If the Brown's decision making was an unforced error I think it could be argued the Dolphins' move was a forced one - but an error all the same.