How do you get the second code for the warehose?

To get the second code, you have to battle one of the Rockets along your way, then afterwards talk to them. One of them will say the code. Before you do, though, you have to make sure that the scientist stole the Sapphire YOU found.

I forgot to answer your second question. You have to go to Seven Island and go to the Ruins. If you go the right way, you will see a building with braille letters on it.

It says that you have to use Cut. So, do so. Then, you will see a hole. Jump down it. Then, go to the top hole and jump down that.

Go to the left hole and jump down that. Go to the right hole and jump down that. Go to the bottom hole and jump down that. You will see the Sapphire template, just to find out that the scientist will steal it. Go down the stairs and exit the place. Fly to Six Island, and then go inside the warehouse.

Go through the annoying place, battle the "boss", then go the top room to talk to the scientist that stole your Sapphire. He will give it to you.

Exit the place and enter it again to talk to the scientist again, and he will explain your Rival in G/S/C, which I found cool because he's giovonni's son. Anyway, go to One Island and give the Sapphire to Celio.

Now, you can Trade with Ru/Sa/Em and now you can catch Mewtwo.

You get the second code from the scientist that takes the Sapphire. To get the Sapphire you must have already helped Lorelie on island 4. Then you can go into Dotted Hole on island 6. Find the Sapphire somewhere in Dotted hole.

Both in the Dotted Hole on Island 6. Kick the Rockets out of the Icefall Cave and enter the Dotted Hole by using Cut to open the door. Then, go down the holes after the first in the order: up, left, right, down. At the bottom is the Sapphire, but a Scientist will swipe it but give you the second password.

In Dotted Hole on Island 6 there is a cave. Go in, translating the braille using your Handbook as to whether you go down the hole on your up down left or right.

When you reach the Sapphire the scientist will steal it and give you the second code for the warehouse. Now you can go to the warehouse and battle him for it back.

He is in the back trying to Auction off the Sapphire on the Computer, he uses Steel and Electric pokemon.

You will get through this, make sure your pokemon are well leveled up and good luck!

You have to go to the Dotted Hole on Six Island. If a man is not in the way, go up to the door blocking the cave. In there there are holes in the floor. If you fall down the holes in the corrct order you'll find the Sapphire. This man will steal it from you and give you the 2nd password to the warehouse.

Hope I helped.

You have to go in a cave on island 6 and when you try and get the Sapphire a man comes and steals it and tells you the second password. When you've beaten all the rockets, the last rocket will redo the switches so you can have a rest, you go back, go through the switch, and fight the man who took the sapphire and you get it. Give it to Ceilo and Voila!