It all happened in the span of seconds in his mind. Overjoyed at seeing Skyfire again after believing him to be deactivated for so long and than spark stopping fear. Megatron would realize that there was more to their relationship at some point and Starscream couldn't let Skyfire get hurt because of that. He was no longer the mech the other thought him to be and never could be. He was now the deceptive, back-stabbing second in command of the Decepticon forces and it was time to show him that. And even though it would hurt them both at least he would be safe. That was all Starscream cared about in the end.
Re: Surprised o_o
And there you go. Just a small little drabble.