Crazy speed. To your point, Tua isn't Vick obviously as a runner. But he should absolutely run more. Those are free yards that he needs to take advantage of more often.
I can't even count how many times Tua would be standing in the pocket waiting for something to happen and would end up getting sacked or making a bad throw instead of taking a positive gain by running a few yards. Nobody wants him to be Justin Fields or Jalen Hurts, but he needs to be aware enough to take the yards and slide when there is nothing else there instead of waiting to be sacked.