FMU question

I know a lot of people say not to use an opk first thing in the morning, because it holds hormones from hours ago instead of your current level. However, I can't take a test while at work. There are 300 people on my floor and most of them women, with one bathroom. I'm just not comfortable with it.

So, what if I woke myself up at 2am, to use the bathroom, and then maybe a small sip of water and back to bed. Test at 6am when I get up for work. That way it's only 4hr hold which is what I tested with otherwise. I test at 6pm and have just gone to the bathroom about 2pm, then stop drinking at 4pm, then test.

Does this sound about right, or okay to use my test this way and hopefully get accurate readings without having to test at work?