Childermass doesn't bother wasting the energy to catch up to Mari until the portal itself, where Papyrus stands forward to block the way. When that happens, he immediately shadow-steps ahead, putting himself at the front of the group.

"She's with us, Papyrus," he says wearily. "We're only taking him to the Ringmaster."

Or so he assumes. If not the medical tent, she would be the next bet. Mari hasn't exactly stated any plans as she marched off with the Warden. The Warden, the Warden, what was his name? It's ridiculous, that stealing a name was apparently so much like stealing an entire concept. Not only from the skeleton but everyone who knew him.