Given the fact that this gave no advantage to Auburn, and the fact that he's still in a boot, this is what I believe happened.
He was hurt after the play. He walked back, realized something wasn't right, then realized he couldn't get to the sideline in time.
Then he flopped.
Anyone saying Gus orchestrated this, strategically, is typical anti-Auburn media bullshit we've grown to expect. There's a difference in that and "flopping" because he was genuinely hurt and couldn't get to the sideline.