Good morning,

Warning this subject contains a **SPOILER**

In this level of the shareware version (E1 M1), at the beginning of the level when you leave the platform while going down, you turn around and you see a passage to the left (see photo N°1).

Once inside and to the left, near the body, a secret wall can be opened (photo N°2), which leads to an apparently locked door (photo N°3), and I couldn't understand how it opens.

I found a lot of secrets in the level, but no key or switch (wall or floor) that would allow me to open the damn door.

If anyone knows how to open that door, thank you in advance.

Photo 1:
https://www.dropbox.com/s/h3wevbbgffi5it0/rott%201.bmp?dl=0

Photo 2:
https://www.dropbox.com/s/1pcdn1efr962atv/rott%202.bmp?dl=0

Photo 3:
https://www.dropbox.com/s/ysebtg7osdyz4fs/rott%203.bmp?dl=0


Edit:

Ok, I just found out how to do it: once the secret wall is open (photo N°2),
you have to wait for the clock to display precisely 3 minutes 00 sec and at that moment,
the door will open.

But be careful at 5 minutes 00, this same door will close definitively and if ever you did not come out in time, you will be blocked in this level.