I had a very interesting night last night, when the Rocky Mountain chapter of AIAA hosted Larry Korb, a metallurgist who had worked for the late, great North American Aviation on the X-15, Apollo, and Space Shuttle programs. Larry made a presentation on his Top 25 people, from Greek mathematicians to Sergei Korolev and Wernher von Braun, who he thought had been instrumental in a series of breakthroughs that led eventually to lunar flight.
He also talked about his own experiences investigating the Apollo 1 (originally "Apollo 204") fire. Larry reported that a piece of instrumentation had been removed for calibration and the plug not capped, leaving an "open" live plug in the capsule that contributed to starting the fire. According to him, North American engineers had been so opposed to NASA's demand for a high-pressure pure oxygen atmosphere that they made NASA put it in a written specification if they insisted on it.
In one of the few things I've ever heard in the negative about legendary space designer Max Faget, he remembered Faget being the one who required an inward-opening hatch on Apollo so it could not be accidentally "blown" in space. That design also made it impossible to open the hatch quickly even without a fire.
Food for thought.
Much appreciation, Mr. Korb.