Response: "Fine. I'll call CPS to look after the child while we wait at the station for your attorney to arrive."
You are familiar with the well known axiom, aren't you? "You may beat the rap, but you can't beat the ride".
To which you reply,
Since you have neither a warrant nor probable cause nor exigent circumstance, I do NOT agree to your request to travel with you.
Further, I will remind you that deprivation of rights under the color of law is a violation of US code Title 18 section 242