We had an ancient steam jet pressure washer around my dad’s garage, mostly for engine degreasing and other serious cleaning. I recall having to be very careful to keep it moving when cleaning engine compartments and to not hold it on a hose or other relatively delicate component for more than a few seconds at a time. It certainly wasn’t at the level of a water knife, but I would not recommend holding your hand under that kind of pressure, even if the heating element was turned off!
(Why they let a teenager, such as I was at the time, operate such a thing is just one of those mysteries of life. I once again find myself asking how I managed to live to adulthood. 
)
