Transfers to a rear naked choke

She slips down onto your back, putting you in a hard body scissors, making you squeal. You desperately try to keep your neck protected, so she tightens the body scissors, you feel it tighten more, putting you in immense pain, so you moved your hands to her legs, trying to pry it off.

Right into her trap, she now can slip her arms around your neck, preforming a choke hold. As the choke tightens you try and think of a way out, but still cant escape. What do you do now...