A total stranger saved my kids today

I was getting my kids into our new/used double jogger this morning in the BC parking lot. I had them in and the stroller packed. I put the lock on the brake and went to quickly put my purse in the back of the car. I shut the door and the stroller was gone. Gone!!!!! I looked across the parking lot and saw them rolling away very quickly it was like a movie that you think would never happen to you. I started running as fast as I could but I wasnt going to get to them by the time they hit the speed bump and went right into the traffic pulling into the parking lot. Luckily the van that pulled in noticed something was wrong and slowed down. Out of the corner of my eye I saw someone running. I looked and saw a young guy with flip flops on running faster than I was. He got there just in time, maybe a foot away from the speed bump. I cried and told him thank you over and over again. I'm so grateful he was there. He was my angel today. I'm grateful my kids are safe, and now I know not to use the brake lock on the double jogger. I almost didn't post this because I felt so stupid and embarrassed but I feel grateful even more so I did post it.