Not to sound like a ****, because i'm no pro myself. But if you're asking this question you'd probably wanna keep it simple, go for the americana or the kimura.
If on the other hand, i misunderstood you, and he was on top of you, you're primary concern needs to be getting free without being submitted.
Or as guys sharper than me say "Position then submission"
"Remember when you are resting, someone somewhere is training, and when you meet him, he will win."