[userbinator]

As I said, you can mix halon and oxygen, and they won't react (even if you try to ignite them).

That makes me wonder if any of the original designers of the oxygen system considered whether a halon-oxygen mix would've been better than pure oxygen.

[cyberax]

Not really. Adding oxygen for sure won't help. Also halon is stored in extinguishers as a pressurized liquid, not gas.