Once you control Jr., turn around and save your game. In this area, you have to be careful not to be spotted by the searchlights, or else you'll have to probably fight a battle. Of course, you may want to--it's up to you. From the save point, head southeast and you'll find a treasure chest that contains a coat - sword inside. Now head up and to the right until the camera changes its view. Continue up and destroy the crate in the center of the screen, backing away if the searchlight is drawn there. Once it's safe, you'll obtain a ruby helmet. Destroying the canister on the left will give you five bio spheres, and destroying the one on the right will give you five med kit DXs. Now head south, following the centerlines to initiate some more cutscenes.
Now you'll be in control of Shion. Head to the left and destroy the column to obtain a defense shield. Head back to the right and then up into the building and use the save point to the right. Now head up and destroy the seal with the ball on its nose to obtain five ether pack S's. Destroy the penguin across from that to obtain a blade soul. Destroy the teddy bear to the right to obtain three bio spheres. Across from the teddy bear and to the right of the pink thing, destroy the snowman to obtain a rejuvenator. Continue right and you'll cause a Gnosis posing as a statue to attack you. Make short work of it, then destroy the golden statue to the right of it to acquire five revives. Head south and take a left, then descend the rightmost stairway and navigate through the rubble to exit to the south. Now head to the left to encounter a Gnosis.
Turn the corner and head to the right, then head down through the hole in the wall to fight more Gnosis. Head to the left, then down through the hole in the wall and fight the next Gnosis you see. Now go to the right and head down through another hole in the wall. Continue down until you're attacked by a Gnosis. Once you're finished with the battle, continue down and open the treasure chest to receive PM card E. Now head back up and to the left until you see a person. Talk to the person to initiate another battle. These types of Gnosis, Larva Dolls, are like zombies, so curative items and ether spells are the way to defeat them. Destroy the large crate to your right and jump into this manhole, then head north and up the stairs to your left to return to where you started. Examine the pedestal with the glowing red button to unlock the door for this area, then head to the left and descend the stairs you see. Go left and under the bridge, then fight the Gnosis. Once done, destroy the wall panel that you see to discover segment address no. 5. Decode it and head inside to obtain the double buster.