He’s SUSPENDED his campaign once before
http://m.huffpost.com/us/entry/ben-carson-suspends-campaign_us_561fa44ae4b0c5a1ce622105
http://m.huffpost.com/us/entry/ben-carson-suspends-campaign_us_561fa44ae4b0c5a1ce622105
You're absolutely right, he did. And he issued a formal announcement. His staff announced his schedule back and forth from the book tour, and took pains to make it known in the media that he was funding the book tour with his publisher's money and his own. In other words, they treated it as any campaign would when announcing a suspension.
Not even close.