It was long ago when I played Prince of Persia 1. Gold times, indeed.
Now, I recalled the old days and remembered one mystery I cannot
solve yet. If you played PoP1 more than one month, you'll probably
know what I talking about.

So, take look at the picture. It is from level 5 and non-hidden.

When you step down and pass through opened gate, that dors closes.
Your only way out is upper gate which can beopened with any of two
switches in middle right sector of room. When you step on the one
of two switches, your shadow - which is released in level 4 run
through the upper gate, drink the potion (which usualy give you one
new hp) before you are able to drink it and escapes from whence it
come. You'll get one hp when you link with the shadow in level 12
but I think you get that hp anyway. Somehow, there are not sense
in that you cannot drink the potion.

The question is: Is there some way to regulary cheat the damn
shadow?

No, There is no way to cheat the shadow anywhere. I ahve tried though, but the game just isn't complex enough to allow some sort of exploit.

To solve this problem, you need to select your C4 satchel charge from your inventory. Use it on the ceiling. A large hole should now appear. Next, select the Grappling Rope and use it on the hole. Climb up, defeat the Orange Dragon with your Machete hidden in your rags and then loot the body.