He laughs a little, because that is a... genuinely crazy idea, no doubt about it. But every solution to their problem, no matter how crazy, is worthy of consideration. After all...

"It really depends on what he'll do once he's ascended. Right now, the damage he causes is relatively limited. He can only draw on us. But if he were capable of reaching across realities, nobody would be safe. Our friends in our home realities would be in danger -- the very fabric of existence could be at risk, for all we know."

But of course, "Even if he had the best intentions, power corrupts. Absolute power, absolutely."