You will come across Aiden and Mila’s Lockers in The Station in the second room you enter. Both of their lockers are closed and can only be opened with the right combination. Aiden’s room is just around the corner and has the clue lying on his table. Pick up the hammer and zoom in to find the right combination on it.
Mila’s locker combination requires a bit more leg work and is split into two parts. The first clue is a ripped piece of paper on a table in her room. Pick it up and progress until you reach the lower deck. Find the conference room and search the large table for the second piece of paper. You can now check the solution to Mila’s locker in the menu.