so i figured it out, but it's basically impossible without a perfect setup. you need to get the green lantern first WITHOUT wasting any bubbles on the red side. then use the vine to travel up to the second fireball on the red side (the fireball that gets you the red lantern), bypassing the first fireball altogether. that should give you an extra 3 bubbles that you would've otherwise wasted getting to that fireball (1 bubble to trigger the first fireball, 2 bubbles to get to the second fireball, and then 1 bubble to trigger the second fireball). then it's all based on luck of the bubbles but it's possible.