Agility is not one of Sentinel's strong points. Nowhere near it. He realises what is happening about 2 seconds after Optimus grabbed his arm but just was simply not fast enough to prevent it from happening.

All too suddenly, he's on his back, staring up at Optimus. Vaguely, he wonders if the red bot is on speed boosters.

"Congratulations," he's not worried. One of his shoulder cannons twitches ever so slightly, changing angle towards that masked face. "Now what?"