How do you get through the cave painting the 2nd time in mt coronet pearl version?

I have diamond but I think it's the same. You have to go to team galactic's building in Veilstone and talk to a man standing outside [I think] then you go to a house next to the building [it says it is the Galactic Warehouse] you go inside,open the door,go downstairs, fight galactic grunts and after a LOT of grunts [you have to go downstairs and upstairs a lot of times] you are in a room where a dude gives you a masterball. After that you go into a room and rescue azelf,uxie and mespit. You do that and the door is opened.