Play half-hole g with the resonator down. Flick the second-to-top left hand thumb key with the B flat and the one just under it when tonguing the A. Drop your jaw, put down the whisper key, and slide your finger from the half hole position to hit the lower octave. Tongue the D, then flick the B flat again. Make sure to play the F sharp with all fingers, the whisper key, and the right hand thumb key just below the pancake key. Give yourself enough half hole to sustain a steady pitch with no trash or octave dropping.
(BASSOON LOGIC. It should make your head hurt.)