WoWDB

To complete this achievement you have to enter the correct passcode during the MOTHER boss fight. The passcode is introduced by clicking a sequence of 3 buttons that you can find in either side of each of the 3 rooms (both buttons in each room are essentially the same one). The passcode is randomized every time, leaving 6 different possible combinations (123, 132, 213, 231, 312, 321). To figure out the passcode, you need to do the following:

• Click one of the buttons, and check if it becomes unclickable. Repeat for each room until one becomes unclickable, which means that you have found the correct start of the sequence.
• Click one of the two remaining buttons, check if it becomes unclickable. If it doesn’t then you’ll have to click the other one.
• Once you’ve found the correct first 2 buttons, click the remaining button and then check that all the buttons are unclickable.

The best way to do this is to send a few DPS and a healer to the second or the third room to check the buttons.
Do all the steps, defeat the boss and the achievement is yours.

Looking for a group? Join the Achievements Discord!

Full Guide: https://www.mmo-champion.com/content/8274-Glory-of-the-Uldir-Raider-Achievement-Guide