maybe u 4got 2 close the cage, the ball accidentally opened out off ur site or they slipped out. a hamster is an animal 4 opportunity. personally i had a few fugitives. the worst is when u have preditor pets like a dog or cat. the best is 2 let them outside or in a room where the hammy possibly wont be in. i set a hamster trap. i put some food inside a bucket or container. it should c deep enough 4 the hamster 2 not escape but not get hurt when they fall in. i stack up a bunch of magazines like stairs. Voila! 1 hamster trap.