Run over to the switch that triggers the platform and leave a Clockwork Bunny there. Then, sprint to the other switch and get the door open. Note: Trigger it before the real attempt to avoid the intermission sequence using up time. Next, sprint to the middle area to the invisible platforms. Shrink momentarily to see where to go. From here, jump off the platform as soon as possible to the invisible beam above it. Next, sprint to the door. Note: You may need to shrink under it to get in.