First outing with big girl underwear: Status=Failure

So Moi has been great going pee pee on the potty at home. She has even done it at friends houses, etc. She usually keeps her diaper dry all night and through naps. Yesterday, She was wearing big girl underwear and had gone pee pee on the potty 2 or 3 times and had kept her diaper dry all night. We had to go to the mall for something and I asked her if she could keep her big girl underwear clean and dry if we went to the mall and she assured us that she could. We got into the toy store and about 6o seconds later, Chris was like "I smell something". Sure enough, she was working on #2. I had to take down her shorts and put a diaper over her underpants, which she was NOT happy about, but it was better than the other result... Anyway, not quite there yet in that department, but I guess we'll keep trying. She's so funny about going on the potty. She said "Are you going to be really excited when I go pee pee on the potty?" and she tells us "Say 'Good Job Moira'" and "Say 'You kept your diaper dry'". She is all about the compliments. Then frequently she'll recite the words from her potty book. Like the whole thing. She says "Now I did it and now I know I can, I can go on the potty and I will do it again! I am a big girl now, I'm as happy as can be, I get to wear big kid pants, I'm so pround of me!". She's got her book memorized.