Roller wasn't really the only one having a little bit of a difficult time taking things in. Optimus confirmed his death, yes. Yet Bumblebee was here now. Alive and relatively well. Then the Prime decided to tell Bee that he actually did something worthwhile.

Megatron an Autobot. Wasn't that too funny.

Thus Bee made his way out. He never did do well just sit around inside. There was a planet at their fingertips that they really knew nothing about. Wasn't it in their best interests for someone to explore a little bit? Bumblebee was pretty good at sneaking around so why not?

Unfortunately, he wasn't quite paying attention. Perhaps Roller would be, since Bumblebee would likely bump into him and fall over otherwise.