Liquid nitrogen would be a "better" option compared to CO2 for the "weaponized aspects".

But, safety in the pits... CO2 stays put in a rather simple bottle.
A dewar bottle with a few liters of liquid nitrogen under the workbench...

If I was an EO, "NO FUCKING WAY".

nah LN2 is a liquid at atmospheric pressure, and hazardous, if you filled somebody else's bot with it enough they could get hurt spilling it on themselves taking their bot out of the arena even if they had waited a bit.

I'll let the idea roll around for a bit, see what falls out.
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Mechanical engineers build weapons, civil engineers build targets

Its OK, my next 'bot will be made of a "Mimetic PolyAlloy"
https://youtu.be/l3V00vZtppg?t=46s

Just as soon as I can get a few more Raspi's onto my cluster and speed up the AI working on the formula..
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Great minds discuss ideas. Average minds discuss events. Small minds discuss people

Another point against Liquid LN2... its cost! And that it counts as a hazardous substance (Well over here at any rate).
The only machine that ever beat another with a gas weapon was one fitted with a Halon Gas fire suppressor fighting another bot that was running a petrol engine... just suffocated the engine. But that is it.
An axe with a hollow spike that could vent CO2 might work if you could puncture the armour but aside from that... no Utterly useless.