Told by Rodimus Prime.
After the battle between Scorponok, Megatron and Shockwave, Scorponok was forced to flee.
The Air Strike Patrol was sent to finish him, right in the middle of a human settlement.
This the Bots wouldn't allow, or at least Hot Rod wasn't going to let it happen.
Scorponok surrenders to the Bots, allowing him to be protected by the Bots since he is now their prisoner.
With the Bots dealing with the Cons, Scorponok leaves the area.