I have many years experience building and operating boilers (water heaters). What it sounds like is that your electric element may have
been inadvertently turned on shortly prior to filling the water heater. Once the water reaches the heated element, you have what is called a flash steam event, which spikes the internal pressure to well over 500 psi. The built in safety valve cannot react quickly enough to vent this much pressure and the result is a ruptured vessel. In technical terms, you had a BLEVE. I do not know where your breaker for the water heater is located, maybe someone else on here can help you. I would take the tt back to the dealer and hope that it's covered under warranty. Good luck.
2010 Silverado 5.3 3.73 EC Superchip, AEM Air Intake
2013 Jayflight 26RLS
2 Fur daughters
....and empty pockets