Wait, what. This is news to Strange whose expression shifts from confused to annoyed to downright worried in all of a matter of moments.

"Is this about the curse? That's why I suggested the Rose Queen plan in the first place!" Strange grumbles. Sure it'd be nice if the Rose Queen managed to take out the Huntsman...but it'd be even nicer if the Huntsman managed to take her out, thereby possibly removing the curse.

"He's got to go back to England," Strange points out, as he removes his hand from Lambert's wrist. "An entirely new age of magic is beginning, he's got to be there to shape it!"

It's obvious that there's a whole host of reasons why Strange wants Childermass back in England that are more than just 'he's my friend and I'm going to miss him.'