Quick change of battery

Allison and I are both traveling.  I called her after I left a conference and got in the car to go see a friend (called her using a bluetooth headset).  We were talking about our days when I came to a stop light.  Since I had very little battery left and I needed the GPS to not die on me, I decided to change the battery in my phone, so I opened the phone, took the battery out, and then realized I had hung up on my wife...