If Shima wasn't on Acquisitions and wasn't someone who already had some contact with Ignatius, Strange would be a lot more reluctant to explain Ignatius's circumstances. Still, he was going to explain them to Childermass anyway, it would be better if more than one person on the team knew.

"Not all, but most of the time. Whoever took him from the temple put a sleeping spell on him. They brought him to this cavern, he woke up, he fled."