After talking to Maple in the basement, Ashley mentions she's going to get something out of the shed. When Ashley goes to the shed to find the package Todd left, it'll give you the option to input a code. The code is 4035364 (same as it was in Episode 4.) Inputting this will get you the 'Memorized' achievement. If you give up on the code, Ashley will open the door automatically but you won't get the achievement.