Most will not have hidden cameras so if you feel unwell and can't get that door open or find the emergency button you might be in there for a long time, or till some steward starts wondering what takes you so extremely long.

There are flights of 24 hours or longer especially now they love to take the longest road instead of the short one. Can you hold in that long? Worse is the public toilet after landing... unless you can make it through the control and find another.

I drink when I travel but not befor I leave... The luck with the buses is that they might stop somewhere where bathrooms are.