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.
I think Whittle's first test run had the turbine overspeed and suffer a catastrophic unplanned disassembly.