I've found that ejecting a Time Machine disk by way of the Finder works just fine. It must be done using a Finder window, however. As noted above, the Apple-E approach doesn't work.

As someone who has taken and administered exams, I can't stress how important it is to read the exam carefully. Depending on how long the exam is, you should try to read the entire exam before you answer anything. Stories of trick exams tend to accompany such advice, but if that is your motivation for doing so, it…

If you're used to "Home" and "End", try using Command-right and Command-left instead. Also, Control-a and Control-e will jump to the beginning and end of the paragraph, respectively.

Telling the rep that you are moving out of the country works quite well, in my experience. I recommend it.

I'll second the 50/50 solution, although a 75/25 (water/rubbing alcohol) will also work if you're a bit more protective.