Help! My husband took off with our son 2 days ago!?

My husband and I got into an argument 2 days ago. He got out of control and got kind of emotional. Apparently, he has been under a lot of stress he has been hiding from me, mostly from work and his parents. He said he was going to take our 2 1/2 year old son out to the mall to blow off some steam and will come back after dinner. That was 2 days ago. I tried to call him, but he shut off his phone. He turned it back on a day later, but is not picking up. Although angry, I begged him to come home for the sake of our son. Through some searching, I know he took our son to the zoo 2 hours from where we live. I don't know exactly where they are. Only the approximate area. I know he is still very emotional right now. He cannot talk or face me. What should I do. I know he will not do anything rash or harm our son because he loves our son so so much. What should I do, though? Some tell me to call the police and file a missing persons report. But I already know that they are both safe and fine and that he is taking good care of my son. My son's welfare is the most important thing to my husband as well. Some tell me not to go to the police, as that will exacerbate the situation, and that I should give him some space to think things through. What should I do?