4200 lumens is actually what an XHP70.2 does at stock power levels, at 30W
4200 lumens x 6 = a bit more than 25 000 lumens.
It still is producing 120W of heat though, so the heatsink behind the LEDs must stay below 60C before stepping down at 3 mins, meaning it must be quite large and heavy to do so.
It is a lot of power, but it is easily doable.
Had they kept their active cooling, I would be that thing could actually do 15 000-20 00 lumens indefinitely.