Okay, let's do some back of the napkin calculation.
The specific heat of Hydrogen gas is roughly 20 J/gC at high temperatures[1]. It would be much higher for a plasma but I couldn't easily find a number.
At 100M degrees C, a single gram of hydrogen would have over 2 Gigajoules of thermal energy. 2 grams of hydrogen would have the same energy as a literal ton of TNT.
It's not untenable, but its not really something that should be brushed off as "its only a couple grams of fuel" or "it can't have a runaway reaction".
Having energy does not demonstrate danger to life and limb. 2 tons of fat have more energy than 2 tons of TnT. Obviously it does not release energy in the same way.
That plasma is at less than atmospheric pressure, and is contained in a massive steel vessel. Even if it expands and melts through the vessel, the atmospheric pressure will collapse it. I do not see a plausible scenario where anyone is in jured.
Funnily enough the much bigger danger is magnet quenches. Thousands of amps boiling off a couple dozen tons of liquid whatever is going to be a hell of a danger, but it's still "violent industrial accident" and not "fireworks factory" - and definitely nothing which people think of when you say "nuclear".
