The article isn't written very well in regards to answering that question. The way it's written makes it sound like he was yelling and shrieking while the officers were encouraging him to breathe. He wouldn't have been screaming if he wasn't breathing. It was reported that he was found "unresponsive." And if that's the case, he wouldn't have been screaming either. The friggin' media has one job, and that's to report a story correctly, and one that makes sense when you read it. This one fails in both regards.
He wasn’t the one doing the screaming. Most likely the guard who found him freaked, especially if it was the temp.