Instructions
Enter the Rocket Hideout underneath the souvenir shop in Mahogany Town. Pass the first "Persian" statue to battle two Rocket grunts. Head west and walk down to find a scientist near a computer. Battle the scientist and press the "A" button at the computer to turn off the statues. Turning off the statues "turns off" the possibility of engaging in a Pokemon battle.
Avoid the wild Pokemon traps scattered along the route to the next floor, B2. Head southeast to encounter a teleporter and a set of stairs. Stepping on the teleporter sends you back to the beginning of the hideout, while the stairs lead to the next floor. Battle or capture any wild Pokemon you encounter on your way to the stairs and head down to floor B2.
Meet Lance before heading down the stairs on the right. Lance heals your Pokemon and assists you in battles. Fight any Rocket grunts scattered throughout the floor with Lance before heading downstairs to floor B3.
Wait for Lance to get the passcode for an upcoming locked door. Walk to the computer room to battle a Rocket grunt. Retrieve the second part of the passcode by "checking" them with the "A" button. Head to the left of the room to grab an item. Head to the lower-left side of the room for additional Rocket battles and items.
Head down the alternate path in the computer room's northeastern corner to go back to floor B2. Walk left to fight a Rocket grunt and head down the stairs to reach floor B3 again. Head east and walk ahead to encounter your rival.
Press the "A" button to open the door. Battle the Rocket Executive Petrel after encountering him in the room; use Pokemon with Electric, Ice, Psychic and Fighting moves to take advantage of his Pokemon's type weaknesses. Follow Petrel's Pokemon back to the locked door on floor B3 after battling him.
Battle Rocket Admin Ariana and her Rocket grunt with Lance's help. Use Pokemon with the appropriate type advantages, such as Psychic, to defeat her Pokemon. Destroy the Rocket Base generators by battling the "Electrode" Pokemon powering the generators after defeating the Rockets. Talk to Lance after dispatching the generators; head outside to leave the Rocket Base.