Spawn a Zeb, stand at the edge of the crumbles, and spin jump to the right a moment after it begins moving toward Samus; turn left just before landing, then do a delayed damage boost to make it under the first gate. Face left again, quickly lose i-frames using either X-Ray or a blue suit, then damage boost again to get under the second gate.

Both boosts must be performed on the last two frames of knockback, to ensure Samus is high enough to reach the gate. For the first boost, jump can be held the entire time. For the second boost, unless X-Ray is available, there is not much time to set up a buffered jump input, so it may be easier to aim to press jump and right simultaneously after being hit.