This is just speculation, but maybe there is a secondary rupture disk that vents the helium inside the room when the primary path (the exhaust to the outside) i

This is just speculation, but maybe there is a secondary rupture disk that vents the helium inside the room when the primary path (the exhaust to the outside) is blocked. And maybe that secondary rupture disk is too strong, so another random part of the helium containment fails, blowing up the machine and possibly injuring the patient. But please note again that this is pure speculation.