"Neither would I, but how could there be hydrogen in there?"
"There shouldn't be. But there's something screwy going on here, and I can't put my finger on it."
"Well, whatever it is, it isn't hydrogen in the reactor room."
"O.K. Stand by. I'm going in."
He walked over to the firewall door. On the other side of it was a small chamber where the oxygen and nitrogen of normal air would be swept out before he opened the inner door to go into the inner chamber itself. There was no need for an air lock, since small amounts of impurities in the He-4 didn't bother anything.
It was just as he turned the lever that undogged the firewall door that he realized his mistake.
But it was too late.
The door jerked outward, and a hot wind picked him up and slammed him against the far wall.
There was a moment of pain.
Then—nothing.