Benjy nodded and ran his hands through his hair, scrubbing them over his face when he pulled them back out. "You never thought to-" Kids were stupid. They made mistakes, they didn't think about the consequences before doing things. They wanted something and they just went for it. Nothing else mattered.
"Tested to see if the potion is doing any other damage to you. Something you can't feel. And to see how to get it out of your system." This thing, untested, could very well have been killing Michael slowly. No one knew.
"Alright. Come on. You're going to explain to everyone, McGonagall, Pomfrey and Slughorn, that you stole the potion and everything that has happened in the interim." Oh. And since your arse will be trapped in the hospital wing, there is going to be an announcement about a dead kid we found yesterday and... Nope, couldn't say that.