Macbook locked during Yosemite Beta installation

I thought I would get OSX Yosemite early by signing up for the consumer beta trial. I downloaded the installation package and started the install. All went well to begin with but after restart the installation stopped due to an error. After a performing a restart, the computer was in recovery mode with just a few utilities available. I couldn't recover from Time Machine because I didn't have an external disk that was big enough; I couldn't erase the hard drive because it was locked and I didn't want to download Yosemite again to find that I would be in the same position 6 hours later. I did a lot of online research and it looked as if I was going to have to use the terminal to unlock the disks. I was reluctantly about to do this when I accidentally discovered a much simpler solution... More: http://www.mwls.com/news.php?n=200