How do you find Mesprit in Pokemon Pearl after it go out of the cave?

Go to team galactic headquarters in veilstone. Then you talk to a galactic mem out side of the HQ he runs away and drops a key. Go inside the 3rd door to your right try to find a second key. After you find the second key get inside the 3rd door to your left find Cyrus or what ever his name is beat him and he tells you where Mesprit is (inside HQ) you WILL NOT be able to catch it but at least you could see it again bring lots of potions revive etc because there are a lot of Galactic members