A solar flare
The team worked fast. They donned their protective suits1 and opened the inner pod-bay door2.
The captain had been outside the space station when the solar flare3 occurred. The solar winds4 that came after had delivered a toxic dose of radiation.
Somehow, the captain had made it back to the bay and was now floating unconscious and limp.
The team administered first-aid5 and started maneuvering through the various turns and sections6 of the station7 that led to the med-bay.
There, they administered the nanites8 that would hopefully save his life. Then, the captain was placed into a stasis tube9. There was no telling how long he’d have to remain there while the nanites repaired his body.