"I don't know," he admits through a mouthful of ham.

He'd been kind of hoping Sinclair would be able to field that question.

But he tries to think. He's deferring to everyone else again, when for once in his life he might be an instigator. What does he know, by observation, about the bathyspheres? About machines in general? Think.

Well, the reason he had to overload the core was because underloading it wasn't an option. Not in that situation. But maybe in this one.

"What if it runs out?" he suggests. "The engine? What if there's no gas?"