The red outlane stays open the entire time.
The gate should be closed like Mk1Mod0's at the start of the game to make two outlanes and open once a "T or "U" upper rollover is completed to create two inlanes. It resets once the outer inlane has been rolled over and you have to rollover the T or U again to open it back up.
There should be two nails there that restrict the gates movement underneath the two wireforms. (Inlanes.)
Playing Future Spa with THREE left inlanes is cheating, which means no boob shower for you Troutfarm!