Before the 1st gate/door going to byakko it's a blue switch so you have to run back to the main entrance and hit the one there then hope someone else doesn't change it once you get back to the 1st door. Then there is no switch before the small room with the double switches that has those two weapons guarding them so you could get stuck between doors with no way to switch. So a cool down could help with this. This is of course if you don't have the HP tuned to you or are trying to get to it solo.

Other wise it's a two person job. If not you and a mule.