After many times of experimenting, I have finally found out how to do it.
I believe the way to do this is the order of the cells you have to open: Please consider the cells i'm going to number. As you turn to your left as you reach the T junction, you will see your first cell to your right. Lets say this is cell #1. As you walk further up, you will see another cell also to your right, which is cell #2.
As you progress along, you will see yet another 2 cells, which will be cell #3 and lastly, cell #4 which is right at the end.
Now, to do this, the numbered cells have to be opened in order accordingly:
#2 #1 #4 #3
I'm still unsure if time is a factor in this achievement but rest assured, I took the time to beat some soldiers/enemies because they were in my way.
Now, for you people who don't know how to get all 4 keys, here's the list below to tell you how to get them.
Key #1: Turn to your left at the corridor where all the cells are and defeat the first solider that stops and attacks you. He will drop a key. Be sure to pick it up because it will only appear on the ground for 5 seconds.
Key #2: Turn right at the T junction instead of left to reach the cells where the prisoners are held captive. Ignore the first 2 cells which the doors have seemingly been blown off. Turn the corner. Half way through running straight, there will be a path that goes to your left. Take that left and head into the empty cell where you will find key #2 in a chest.
Key #3: Be sure to by a Sunstone from Genma to make life easier. As you make your way to the first dark corridor, use the sunstone. Be sure not to be killed or your sunstone will disappear. Destroy the third stone gargoyle to reveal a mouse hidden in the alcove. Connect with Rico and then talk to the mouse. The mouse will hand over a cell key.
Key #4: To get key #4, you need to get Edward into your party. Make your way all the way to the top of the castle until you get a cutscene. When Edward arrive in your party, use item creation to make a cell key. To make this cell key, you need 2 things: 1x metal fragment 1x marble
To get the marble, it is hidden in an invisible chest. To find this chest, there should be a cell somewhere above the floors. You will know if it's the right cell because it's the only cell that's on the higher levels and it contains many boxes and other apparel. Go behind the boxes and play your flute that reveals hidden items. You will know its the right place as you can hear a strange nosie and wavy background.
My method of getting this achievement:
I'll be brief, this is how I got it:
1) Get key #1. Open cell #2 2) Get key #2. Open cell #1 3) Get key #3. Open cell #4 4) Get key #4. Open cell #3
Well, I hope this works for all you guys. I see that many of us have been scratching our head for hours how to do this. So in conclusion, I believe opening the cells in a particular order is the only way to get this. Good luck to all.
And if you still don't believe me, check my gamertag: InspirAsian
this will deff help out alot of people, and me as well (as soon as I beat the game and start it up again on Easy difficulty to get the achievements I already missed)
There's a couple of other achievements I was wondering if you have ways to get them, but not sure if your that far into the game yet...(probably not, assuming you just did this part in the game then posted this)
ah ok, then do you have a way to get the tsunami (spelling) one? I know youhave to somehow not get hit by the tsunami's but I dont know how not to get hit by them lol another one is the one where you have to recuse the lil boy without him getting injured, each time I tryed (I failed like 2 or 3 times thanks to the bird lol) and was wondering a way about that one as well. Also, do you know which stage it is that you have to blow up all the barrels on? (for the barrel of lulz achievement)
I'm not up to the tsunami as of yet, but i've heard it's a tough pickle. The 'For the children' achievement got me into frustration. That's why i'm going back to easy to see if those snakes are any easier, so i don't have any tips for you on that one.
The barrel of lulz achievement is in the very first stage, where you have to escape.
Have you noticed the achievements are in order with the story?
Barrel of lulz On the run Rock, stock and barrel Capell of the rescue
We'll so far Ive only gotten a couple of em, so I wasnt sure if they all were inorder (we'll, the main one I had in question was the barrel of lulz) but thats good to know. The only thing that'll be a pain is trying to blow up the barrels while running from the Troll...or can you go back down all the stairs after knocking the Troll off the top of the stairs to get the ones I mighta missed? or do you know?