This achievement is earned in Act 4, Part 2 when you’re resetting the power switches for the Time Machine.
It is missable.
You have to let the cutscene that begins after going through a door play out in order to unlock the achievement. The cutscene begins right after you open the door in the room that contains Jacks stuffed giraffe and he mentions something about Will keeping all of their family’s belongings. You can just redo the level if you skipped the cutscene.