Online is important, but so is...
1. Pre-snap reads, knowing what will be the best read prior to the snap.
2. Actually seeing this come to fruition, throwing the ball before the break.
3. Pocket movement, not running. Avoiding the rush while keeping your eyes downfield.
3. Quick release, getting the ball out in time, on stride. Marino and Romo were known for their quick release's. Dak looks like he is in slow motion when he is finally ready to throw. Roger's seems to flick his write and the ball is gone.