Where's Mattie?

All the doors in our house have levered handles instead of the round knobs...pretty decor but not great for children! About a month ago, Ella was finally tall enough to reach the door handles. Within a few days, she started opening the doors trying to make a great escape! The only positive about this situation is that she now helps let the dogs out to potty :) The dogs will go to the back door and Ella immediately goes over to the door and tries to open it to let them outside. She'll even let them back in when they come back to the door and bark! Since Ella has become so fascinated with the doors, we watch every move she makes and we've gotten in the habit of locking all the exterior doors. On Sunday, I walked into the bedroom for a few minutes and I heard the garage door shut. When I came around the corner, Ella was standing there smiling. I was just thrilled that she actually shut the door and didn't try to go outside or fall out the door onto the cement. I had just went outside a few minutes before that and had forgot to lock the door behind me. Ahhhh! About an hour or so later, our telephone rang. It was our neighbor from up the street. He asked if we knew that one of our dogs was out playing in the ROAD!? Oh my gosh was he serious?! He said he had approached her and she came running home. How did we not know that Mattie was missing? And how did she get outside to start with? Then we remembered that Ella had opened the door and that's when Mattie made HER great escape! I can't believe we didn't realize she was gone? Now, I make sure everyone is inside and accounted for and the garage door is LOCKED!! Poor Mattie :) I gave her a piece of cheese (her favorite treat since she's allergic to real dog treats) and I think she forgave us!