Savaross doesn't take infants when he goes out looking for apprentices; the years when they will need care and be unable to make themselves useful are a nuisance. But seeking apprentices is not the only reason he leaves the tower, and it is unwise to look a gift horse in the mouth.

He carries the babe away from the burning wreckage of the now-dead witch's abode and hands her over to the care of the older apprentices on childminding duty. 

Savaross doesn't take infants when he goes out looking for apprentices; the years when they will need care and be unable to make themselves useful are a nuisance. But seeking apprentices is not the only reason he leaves the tower, and it is unwise to look a gift horse in the mouth.

He carries the babe away from the burning wreckage of the now-dead witch's abode and hands her over to the care of the older apprentices on childminding duty.