Megatron doesn't feel super compelled to leave here, but he can hazard a guess that it's the same mysterious force drew that him here in the first place that's causing that, and he'd rather follow a suggestion from Optimus than submit to whatever the hell that is. Let's have that walk; it sure as hell doesn't seem like there's anything to be gained by staying.

"No," he agrees. "And I've never known organic life forms to be able to breathe the atmosphere, either." He glances at Optimus. "Have you been here for long?"