NASA just scared the heck out of a lot of International Space Station (ISS) followers when it accidentally aired an emergency medical drill during a livestream.

According to CNBC, the livestream on Wednesday evening was abruptly interrupted by a speaker announcing that an astronaut on board the ISS was suffering extreme compression sickness and may need to be placed inside a spacesuit filled with pure oxygen. The voice reportedly advised ISS crew members to check the astronaut’s pulse one more time before proceeding and warned that the oxygen suit was only a “best effort treatment.” It said the astronaut’s prognosis was “relatively tenuous.”

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