How to get to Purple Palace (Secret Zone) - Sonic Triple Trouble 16-bit Remake

Tutorial on how to get to Purple Palace in Sonic Triple Trouble 16-bit. The zone is located in a pit near the end of Robotnik Winter Act 2.
0:00 Robotnik Winter Act 2
4:25 Purple Palace
Special thanks to NinjaChael on Twitter because he stumbled upon it by accident and because he was posting screenshots from the game I was able to deduct where the secret zone is.