The safety was dropping to his spot as a single-high. If Goff had looked for Watkins, he would have moved back over the top of Watkins. Maybe he isn't able to recover. But if Goff is looking at Watkins, maybe Scandrick takes outside leverage and sticks with him. That would change the play entirely. All we know is that the defense reacted to what Goff did. We don't know how they would have reacted if things were different. We also know the outcome of the play was a 29-yard completion, so I'm not bothered by it.