dear magtro.
i play now,(black mirror 2),i try my best,to follow your
WT,word after word,so far so good,but when i came to the
allmost end of chapter 1,you say,(go home and enter the
bathroom.)Darren will never enter the bathroom,instead
he starts complaining about some items,he must have in
order to make the developings,he will list them also.
here is the solution,instead of going to the bathroom
go to the kitchen,put the mouse under the sink,you will
see the words,(cupboards)highlighted,left click 1 or 2
times,the cupboard opens and a tray jumps into inventory
maybee some more things also.THATS IT.now Darren will
say he has evrything,he goes by himself to the bathroom
maybe not,if not click on the bathroom,the main thing the game goes on,without any problem.
from samuel schwartz

Many, many people have used MaG's Black Mirror 2 walkthrough without a problem. I don't believe that the game is a strictly linear one, so you probably performed some actions in a somewhat different order from the walkthrough. The walkthrough certainly isn't wrong.

I'm glad you've made it to chapter two.