“This was an unprecedented event that instantly and catastrophically damaged highly sensitive Tabcorp hardware.
“This occurred in the part of the third party-owned data centre that Tabcorp uses. Prior to the incident, there was no indication that any mechanical failure was imminent.”
The air conditioning unit is believed to have been Global Switch's rather than anything installed or operated by Tabcorp.
Global Switch uses the Inergen gas suppression system, according to its technical specifications [pdf].
There have been data centre incidents in the past where the pressure of the gas release caused vibrations so severe that it damaged the racked equipment.