The problem with your design is that for some reason you want the player to know where the bathroom is, but not where everything else is, which is pretty odd, especially if the character the player takes role of, lives in the house.
You can never force the player, only suggest, and when you restrict him, make it logical. You want the player to rush to the bathroom in the middle of night, but you forget that player and main character is 2 different things, the player is a guy playing amnesia and hes used to exploring the unknown, while the main character is a man who has an urge to go to the toilet(which you cant give the player)and he has seen the house many times so he would not care to go look around, especially not in the middle of the night, The man is tired and just want to hurry and get it over so he can get back to bed while the player is excited to look around and wants to proceed. this is the flaw of your story.
now what can you do about this?:
1. change your story so it becomes more logical if possible
2. Use a cut scene, cut scenes are the only times you can get the player to do something spontane/specifik while they have other options.
3.why would going to the toilet in the middle of the night be important to the story? Im guessing there would be some sort of thing in the bathroom, you could have the player wake up hearing a sound or something which would then have the player looking for the bathroom(now that I think about it this dosent really solve the problem, but oh well)
4.if the player leaves a certain area have them die with the dead message "you wet your pants".
also i would like to comment your own suggestions:
1. tellin the player to act how she/he would in real life dosent change anything, since she/he will be acting from her own viewpoint and not the character's, in other words its not realistick to go to the toilet when you dont need to pee, and you rather want to explore.
2.adding a corridor and a block box is really just a way of trolling the player, since a corridor hints that the player should go there and then not allowing them to do what you unconsciously told them that they should.
3.Yes i know i said that the player and the character are 2 different things, but from the players view point its the same. Now having the players want to do something and then being told by themselfes that what they are doing is wrong, is odd, but most importantly it pulls the player and the character far appart therefore ruining the immersion.
4. I dont think its necesary to repeat myself.
Final words:
when you design your story, you must accept that the player has free will, since its necessary to make the player feel immersed. in the original amnesia campaign there was nothing that prevented you from things like, fx this
http://www.youtube.com/watch?v=745LhHN4WBI which would actually kind of ruin the experience, but frictional games trusted the players to take the game seriously, instead of wasting time forcing players who wanted to play differently to play it their way.
If you really want to control whats going on, want things to happen with the right timing and everything, i suggest making a movie's instead.
ps wrote much so no, i did not check my grammar