I'm learning not to leave ANY door open for ANY amount of time... I don't know how he can make so much mess in so little time! My only consolation at this point is that he hasn't figured out how to open those doors, but I know it's only a matter of time.
Perhaps a second round of baby-proofing is in order. I love catching him in the act he always tries to leave the scene as fast as possible, or look at me with his elfish mischief-making smile (I'll try to capture it, it's pretty amazing), or another tactic we love is the classic "I'm so cute how can you be mad." He accomplishes this by saying "hug?" several times with arms wide open and waiting. I'm sighing right now. He makes me crazy but I sure love him.