Deus Ex: Mankind Divided Achievement/Trophy Guide - A Heated Combination (Mission One)
To attain this achievement/trophy, you must input the correct numbers into the very first keypad that you come across in mission one. When you first reach the keypad, you will notice that it is powered down so you are required to turn on the power again which can be done from jumping up on the beams and following the path to the switch. After turning the power on and make your way back to the keypad and input the numbers '0451'. This will unlock the door immediately, so you won't have to hack it.
This was a little Easter egg callback to Deus Ex Human Revolution when Sariff changed the passwords because someone was stealing ammunition which itself is another callback to a character named Shannon that appeared in the original Deus Ex that stole weapons and ammunition.
I have added a video guide below,