The SC will inform you that Power Bomb data is ready for download in the Sector 5 (ARC) Data Room, so we'll head back there straight away. On your way down the Main Elevator don't forget to pick up Missile MD.04. Once down in Sector 5 work your way over to the Data Room to finally pick up your first Power Bomb! Once again we'll have to go right to get back to the Navigation Room from here.
Drop down the frozen shaft adjacent to the Data Room and go left. In this next shaft we'll explore a new area of this sector. You'll notice that the green creature normally in this room has vanished, lay a Power Bomb and watch as it blows open a hole in the floor where the creature used to be. If you keep going left through the yellow door past the Save Room you'll find a destroyed door, so we won't be able to go down that tunnel. Instead drop through the hole the Power Bomb blast made and go left. You'll now be in a long dark corridor that appears to be empty. Run forward as fast as you can as the door will open behind you and the SA-X will come prowling in!
If you're quick enough you should be able to get ahead of it before it sees you, but if it spots you and starts firing the Ice Beam, quickly hit it with an Ice Missile to freeze the creature. Fly through the corridor and lay a Power Bomb at the dead-end to open up two tunnels in the wall, quickly go through the upper tunnel and head through the door at the end of the corridor. Watch out for the SA-X's projectiles as they can still pass through the wall to hit you. Once you're safe in the next room, fry all the creatures to regain your health. Lay a Power Bomb here to blow open an opening above this small room and to uncover Power Bomb S5.01 in the corner.
Climb up to the two doors above and lay another Power Bomb to reveal a large opening in the roof. Climb up and freeze the Rippers flying about to climb up to the door at the top of the shaft. Inside you'll find Power Bomb S5.02 waiting. Leave the room and drop back down the shaft. Go through the left door and proceed through the Security Room to make your way through the tall frozen shaft you've been through before.
At the top save your game in the room beyond. From here we'll be going back up through the huge frozen room but you'll be able to pick up Power Bomb S5.03 on the way, although it's a tricky one. In the next corridor adjacent to the giant frozen room you'll encounter a huge creature blocking the way, use a Power bomb to destroy it. Once you finally manage to snag the Power Bomb, head back up to the Navigation Room for your next fun objective.
Once you reach the Navigation Room the SC will bluntly tell you to return to Samus' ship in the Docking Bays. Nothing too tricky, leave this sector and ride back up the Main Elevator. But, there's a problem. As you ride up the elevator, about halfway up it'll unexpectedly shut down and trap you in the elevator shaft. Now something really nasty is going on. Samus isn't one to be trapped like a rat, so shoot open the right side of the shaft to find an opening leading into a hidden tunnel. It seems that the power has once again gone out, but this time it's more serious.
Traverse through the next corridor while watching out for the little spiky creatures, fry them with two missiles each. Crawl through the hole up in the top right corner of this room to find yourself in the Sub-Zero Containment room. This frozen room has even more bad news, straight in front of you is a massive frozen creature that appears to be Ridley! Even though you've already defeated Ridley and blown Zebes apart, somehow here he is, frozen solid. Walk forward and the creature will abruptly crumble to pieces. Before you can heave a sigh of relief, you'll see a flashing Core X drift out of the remains and float away, we'll be seeing that creature again soon.
For now drop down through the small hole the remains create in the floor. Down in this dark tunnel you'll be able to find Power Bomb MD.01. Cross through this tunnel and clear out all the spiky creatures. You'll need to charge forward to the right to break through Speed Booster blocks in the next room, just watch out for the creatures above dropping down slime. Once you break through all the Speed Booster blocks in the following corridor, lay a Power Bomb to reveal Missile MD.06 and a passage leading up. Grab the missile and head down to your ship from here for your next objective.