Evil Inside (HP)

Starting on Round 3 you can open the small chest on the dresser by the front door, the code to unlock it is 2951.
I show this Achievement in my Walkthrough starting at 3:05 minutes into the video.
Timestamps below.
0:20 Round 1
1:19 Round 2
3:00 Round 3
3:05 Master of unlocking
4:29 Round 4
5:05 Secrets in the dark
6:49 Round 5
7:49 LightAtTheEndOfTheTunnel
8:39 Round 6
8:55 The Observer
10:14 Memories
10:57 Round 7
11:16 Be ready for the BBQ
11:56 God ends here
13:02 Round 8
13:05 Music for my ears
14:22 Round 9
17:04 Round 10
17:19 Back to life
18:38 Round 11
18:45 Perfectionist
19:05 Smile
19:36 Discover the truth
20:10 See the name of Gods