Proof? Hell. "I don't exactly have anything on me at the moment that would suffice as such," he says a tad irritably. "Especially considering that I don't even know what part of Cybertron we are on! So how-" Ah. Wait. He has an idea.

"Megatron! Assist me in locating Megatron, he must be somewhere here on the planet, and surely he will corroborate my claim!" Or shoot Dreadwing dead again. Either way it's a win for Starscream. "Only stop shooting at me long enough for us to locate him! and if it turns out that I'm lying... you can both, ah, rip my spark out, or whatever such physical punishment seems suitable to you." He shuts his mouth and ducks inside a burnt out building, all senses on full alert as he awaits a response.