Gas will instantly kill all enemy units (even tanks and copters)

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When gas is used the game gets a list of all map units, checks if the unit if infantry, subtracts a small portion of HP, and if the unit's HP goes to zero it kills them. This makes it so that instead of checking if the unit is infantry it just jumps to the section that kills them.

Wont that also kill your units (broken image removed)

EDIT:It seems that the gas still kills your loyal minions but slowly
Maybe an AoB for the gas having no effect on your troops will work?

Own units don't take gas damage
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You could also do this.

No unit, yours or enemies, will take normal damage.
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With this cheat you wouldn't deploy any minions. Just buy six turrets, let the enemy close in and start an endless battle with them, and then use the gas when you're ready. Your base building will still be vulnerable, but I never found that to be an issue.