Tesla’s Cybertruck unveiling last week was one for the ages. Aside from introducing a tank of a truck that looks like it belongs in a futuristic military movie filmed in the 80s, a demo meant to highlight the Cybertruck’s armored glass didn’t go exactly as planned. As you’ve likely seen by now, two of the truck’s windows shattered immediately on impact when Tesla designer Franz von Holzhausen threw a metal sphere at them. The sphere didn’t make it into the truck, but it was embarrassing turn of events nonetheless.

Elon Musk, who was naturally a bit flustered and surprised, quickly blurted out an expletive before joking that von Holzhausen perhaps threw the metal projectile a bit too hard. Musk later added that the same experiment worked swimmingly before the official presentation, and even offered up video evidence as proof.

Naturally, the failed demo elicited an avalanche of laughter and hilarious memes from folks online. But if we move beyond the comical aspect of the demo-gone-wrong, you might be curious as to what exactly went wrong.

Interestingly enough, Musk himself provided some insights about the shattered windows via Twitter. As Musk explains it, von Holzhausen hit the Cybertruck with a sledgehammer before throwing the metal sphere, all in an effort to prove how resilient the vehicle was. The sledgehammer demo, according to Musk, cracked the base of the glass and helps explain why the window shattered.

Providing even more insight into the matter, a moderator on the Tesla subreddit talked to a Senior Reliability Engineer at Tesla for 30 minutes about the incident and relays some interesting tidbits.

I talked to a senior reliability engineer at event and held the 1 kg steel ball Franz threw. He said they threw it 5 times the night before with no issue, and suspected microfractures were root cause. Interestingly, they had spare windows on standby and fixed it within 45 minutes. But they chose not to use the fresh windows during event. They also recommended to Elon that he should NOT try it, and instead just stick with the ball drop gag.

I told him that before I crossed over into astronautics, I used to be a blast & ballistics research engineer who tested blast-proof and forced-entry-proof glass for US embassies, so I ended up talking to this guy for like 20-30 minutes, gave him some of my lessons learned and recommendations about fastening, and got a lot of great info from him in return.

He was a super nice guy, obviously a bit shaken up by the ordeal. By the end of our convo, he offered me a job lol.

Perhaps the least surprising aspect of the entire ordeal is that everyone at else at Tesla advised Musk not to go ahead with the demo. Musk, though, has an unabashed flair for the dramatic and sometimes cannot be constrained by logic or reason. Not that we’re complaining, of course, as video of the windows shattering will keep us laughing for quite some time.