After reading the new article for the Rebel Commandos, I went and re-read the rules for Arm X and Detonate X. In the current rules, if there is a Proton Charge Saboteur on both sides, then I see nothing preventing a player to detonate a charge that was just placed by the opponent. The rules say:
"After a unit controlled by any player performs an action, each unit that has a weapon with the detonate x: charge type keyword may detonate x friendly charge tokens of the specified type. See “Detonate” on page 26."
"If, after a unit performs an action, both players have units with the detonate x: charge type keyword that could detonate charge tokens, the player that does not control the unit that just performed an action may use their unit’s detonate x: charge type keyword first."
The Arm X is an action, so this scenario is possible:
-Blue player Proton Charge Saboteur uses his Arm 1 action to place the charge.
-As a unit from the blue player just performed an action which is the trigger, the red player Proton Charge Saboteur chooses to use the Detonate 1 abbility to detonate 1 charge, and chooses the one the blue player just placed.
Am I missing something or this is a legal move actually?