It's the door you use to go fight Adam and the others in the tournament (if you speak about the door to start the chapter).
I have an other problem :
What should I do after activate the generator ? I check the room where they told us to go and use rock smash but i'm don't know what to do after.
Do you what should I do ?
Thanks
Edit: just Fount how to do it , I forget about the blast powder