Do you suppose it's temporary, or... [Probably too soon to tell.
With Jack, he could feel his soul (or ghost, or lifeforce, or however you want to define it) abandon the body, and then bounce back. He'd felt no such thing with Ianto - mainly because they had not yet met. It's awful, but he thinks if they had known each other prior, he might have better insight into what happened between dying and coming back.]