Car Problems??

This morning I walked out to my car, threw my purse in and started it... then I noticed an empty smoothie cup from yesterday and I didnt want it to stink up my car so I ran it inside really fast. However when I came back to my car....THE DOOR WOULDNT OPEN! It looked unlocked, but it wasnt. For some reason my car door just decided to lock itself...while it was running..with my purse inside. The reason my purse is significant is because the only other extra key..was sitting inside my bag. My dad came out and tried to hanger the door with zero success, so I had to take my mom's car to work. My poor Jetta was left locked and running in the driveway. And I was 15 minutes late for work. gah.