> All that coolant flow and all that electrical power in a crowded space is scary.

Maybe it's a non-conductive oil? I recall seeing someone who overclocked their PC (circa 2005) to 5GHz, and ran the motherboard completely submerged in an oil bath.

Listen to the video again, he clarifies early on that this is supporting multiple racks. A megawatt is 1000kW. If you took 5 B300 systems (10 rack units each), you'd still only be at 75kW, which if you're doing redundancy properly, means you have wired 150kW to the rack, but you're not generating a megawatt of heat.