X DiVERockman X DiVE Zero-zeries x X DiVE Collab Event, How to get Fourth Deep Element

Really long title, I know. I saw a lot of people saying that the last gate does not open, even if all of enemies near it were killed (myself included). Well, no. You need to go down after the first gate, get on the platform, wait until it goes back, kil--... CLEAR-UP red enemy repliroid with a bazooka in their hands that will appear on that rock platform and the gate will be opened. Well, I'm bad at explaining, just watch the video.