P.P.S. I would never ever had stood radially from the turbine. Off to one side is much better. At least he wore goggles. I'd also put a thick plate of steel between it and myself, and watched the engine via a mirror. Looks to me like there was no speed control on it, and a lot of power running through it.
I think Whittle's first test run had the turbine overspeed and suffer a catastrophic unplanned disassembly.
The Whittle story is a little more involved than that. His first run didn't go boom, but it did go out of control, get red-hot, and need to be shut down by cutting off the fuel pump. It didn't stop immediately, though, which is a terrifying failure mode.
It took him a couple of years to sort out the design problem that led to unburnt fuel pooling where it shouldn't.
BTW, Whittle invented the radial flow turbojet. Ohain invented the axial flow turbojet, from which all modern turbojets descended from.
P.S. Being an old guy, I'd have been pretty concerned about a turbine burst shredding my body.