I couldn’t have typed a better summary of the discussion than this. Nuclear codes are a thing that exist for a reason - it is not admin abuse to provide them or to allow the captain to self-destruct the station in response to an immense threat such as a sentient disease, especially with proper RP procedure followed regarding it.
The aheal is where the problem lies. An ERT or even a Deathsquad would have been acceptable to ensure the eradication of either the disease or everyone infected with the disease based on communications between the Captain and CentCom, but a straight up aheal without even a prayer is bringing OOC intervention to an IC situation.