"I could," Strange responds. "But then what? I wouldn't be able to get to the healing temple that quickly if he takes a bad turn or something odd happens with the brand."

Because at the end of the day, Strange still doesn't really know how iron would interact with a fae turned skink who had a lot of his fae-ness removed already. Ignatius is just a puzzle of complications and Strange has absolutely no idea how it would turn out.