Options in the wild

A few weeks ago I was travelling on an international business trip.  On the way back I came to the top of an escalator to face the immigration / passport check area.  It looked like this:

(only the lines were a lot longer)

I just jumped into the line that was right in front of me and then sort of observed the lines.  The mental schematic I put together was this:

So I moved through the crowd to line "b" because it was the shortest one I could join (since I don't hold a EU passport).  Also, I realized that there were to windows serving that lane... both window "a" and window "b".  No wonder the line was shorter!

A minute later, the situation looked like this:

As the efficient, German airport had recognized a long line and opened window "e" up, and a mad dash had taken place as people near the end of the line for window "d" scrambled to be at the front of the new line.  My old location at the end of line for window "d" would have put me in pole position for the newly opened window!

Then, a minute later, this happened:

When the crew for some flight showed up and took over priority on window "a" and window "b".

Being a ridiculous person I thought "This is fantastic!  What a great example of real world options analysis!!  I can't wait to write this up!"

What are the options?  Take a few minutes to think about it.  In a few days, I'll publish my thoughts on it, but I would really like to hear what others say, too...