When did the class clown go way too far?

At my high school, we had this guy who would literally do ANYTHING for attention. This dude once stapled his hand to impress a girl and didn't even flinch. Everyone thought he was hilarious except one person - our chemistry teacher.
Our teacher was crazy strict about lab safety. "These chemicals can permanently harm you," he'd warn us constantly. The class clown would always mock him behind his back and call him "Safety Sam."
During lab one day, our teacher got called into the hallway. The second he stepped out, the class clown's eyes lit up with that look we all knew meant trouble. He spotted a beaker of clear liquid on the teacher's desk and snatched it up.
"Who wants to see me drink some mysterious lab juice?" he announced with that stupid grin of his. The liquid looked exactly like water.
"That's insane, put it down," my friend hissed. "You have no clue what that is."
He just laughed. "Relax! I watched him fill it from the sink earlier. It's just water."
As he stood there holding the beaker, this kid from the back of the class shouted, "I bet $100 you're scared and won't do it!" The room got silent. Everyone knew he'd never back down from a challenge, especially not with money on the line.
Before anyone could stop him, he threw his head back and gulped down half the beaker. For a few seconds, he stood there smirking, basking in all the attention.
Then everything changed. His smile vanished. His eyes bulged. He started making this gut-wrenching gagging sound. The beaker crashed to the floor and shattered.
It wasn't water. It was a diluted hydrochloric acid solution for our experiment.
Complete chaos erupted. Girls were screaming. Someone bolted for the nurse. He collapsed to his knees, desperately spitting and clawing at his tongue. His face turned scarlet and he was actually crying. I had never seen genuine terror in his eyes before.
Our teacher burst back in and instantly assessed what happened. Without hesitation, he grabbed the boy by the collar and dragged him to the emergency wash station. He forced his head under the stream, making him rinse and spit repeatedly while someone dialed 911.
Paramedics arrived in minutes. They stuck an IV in his arm right there in the classroom and rushed him out on a stretcher. The entire school stood frozen in the hallway as they loaded him into the ambulance.
He spent weeks in the hospital. The acid had severely damaged his throat, vocal cords, and esophagus. When he finally returned to school, he couldn't speak above a whisper. The doctors said the damage was permanent.
The worst part? His entire identity had been built around being loud, being the center of attention, making people laugh. Now he sat alone at lunch, writing notes instead of talking. Nobody knew how to act around him anymore. His friends slowly stopped waiting for him after class.
Six months later, his family moved away. I heard from someone that he had to switch to homeschooling because of the depression and anxiety he developed. That brief moment of trying to be funny – that single stupid decision – had completely shattered his life.
One day before they left town, I ran into him at the convenience store. He looked completely different - thinner, hunched over, eyes always on the ground. When he noticed me, he pulled out his phone and typed something, then showed me the screen: "Tell that guy I won the bet. He still owes me $100."
Sometimes I still think about the look on his face right before he took that drink. So confident. So desperate for our approval. If just one of us had physically stopped him instead of just saying "don't," everything would be different.