The first is that the lights are controlled by motion in the bit between the outer and inner doors, so as you go in, if the lights are off they come on, and they are switched off on a timer five minutes later if the movement sensor hasn't been triggered again. (You can probably guess where this is going.)
So in you go, the lights come on, you go into a cubicle and start to do your business. Perhaps you've had the foresight to smuggle in a book or magazine, or you play with the settings on your phone (I can't be alone in this). After that five minutes, though, unless someone else has come in to the toilets in the meantime, you are plunged into a darkness so black it makes a moon-free night in the middle of Salisbury Plain look like a supernova.
The first time this happened to me (yes, it's been more than once) I was scared witless because I didn't know what was going on. I thought perhaps the whole building had lost power and everyone was now evacuating (pun not intended), and poor old me would be found days later by a team of sniffer dogs, still sitting there. Or that my colleagues were playing an elaborate practical joke on me and would all be waiting outside with a load of cameras and silly string. Thankfully not. I had trouble believing it could be something as monumentally cretinous as the timer for the lights, though.
I mean, who actually decided on five minutes? A committee? An individual? Which individual? Or is it perhaps the default setting for this type of timer switch, and nobody had the foresight to consider if it was appropriate? Or perhaps I am alone in occasionally wanting to take more than 5 minutes over my oblutions?
All those unknowns aside, that's how it is. So what do you do in this situation? Well if you're me, there are sometimes as many as four options, three of which actually reduce the crisis scale of the situation from a 9 to a much less severe 6 or 7.
The first approach is the best but it relies on me having my keys with me. On my keyring is a tiny blue LED light which is just one of those boy-scout, be-prepared kind of things I have a habit of carrying. This is great because it's quite bright, and directional, and when clamped between the teeth will illuminate brightly until the bite is loosened. But I often don't have my keys with me; I tend to keep them on my desk.
The second is the mobile phone. They emit light when you press a key, so just press one and the cubicle is faintly illuminated with a hue directly corresponding to the average colour of your chosen Nokia wallpaper. If you hold the phone in your mouth you can finish your business with the only other hassle being that you have to press a button every 30 seconds to keep the backlight on, or else change the duration of the backlight-off timer on the phone, which is hardly worth it. If you've good tooth control you can press a button with your teeth but be careful you don't inadvertently call the emergency services. The phone is also good because I usually have it with me.
A cigarette lighter is the third and final light-emitting option, but not a terribly good one. Firstly this is because I don't often have one since I don't smoke at work, and secondly, there are the obvious heat implications. A lighter can't be held between the teeth, not when illuminated anyway. So it's the least preferred of the light-emitting options but still better than complete blackness.
The fourth thing to do, which is where you have no light-emitting device at all, is just wing it. Imagine being blind, perhaps, and just get on with the task at hand with no external illumination. Go on past experience, as it were. I can say that finding your way out of the cubicle and over to the inner door in pitch blackness is no mean feat, even if you're familiar with the layout. A fair amount of stumbling is to be expected before the lights are re-triggered and you can get on with washing your hands.
The risk inherent in any of these situations is that while you are sitting there in the dark, someone else may come in to the toilets and discover that you have been doing so, which could be quite embarrassing. So here there are a couple of options.
If you stay completely silent, they may not notice that you are there, and you can wait for them to do their thing and leave, and then you can finish up using the light remaining from their own triggering of the sensor... basically a full five minutes after they leave (since they trigger it on the way out as well, of course), which is probably ample. But if you stay silent and they do spot you, that's surely even more embarrassing than the fact you were sitting there in the dark, because you were trying to hide it. They would either, I imagine, rip the piss shamelessly, or pretend they hadn't noticed.
Another approach is to make no pretence about the fact that you were sitting there in the dark, or perhaps even make some comment about it, along the lines of "Ah, thanks, couldn't see a thing." But in this case, if they weren't going to notice you, you've drawn attention to yourself unnecessarily.
It's a big dilemma.
Personally, I would remove the problem as well as the dilemmas it creates, by installing noise sensors in addition to the movement sensors, so that when the lights went out you could issue a sharp hand-clap to bring them back on again. I would do it building-wide (there must be the same problem in the ladies, and all the other toilets in the building, I imagine), advertise this toiletary comfort and safety enhancement in the company newsletter and receive congratulatory praise and admiration for months to come.
The second thing worthy of note in the toilets is a sign that says "Please call the helpdesk on 3412 to report any faults in toilet areas." What a remarkably considerate message from the Occupational Health people, I thought. On one occasion I felt I had a use for it, because it was stinging slightly when I peed. So I called the number and left a message, but nobody's got back to me as yet.