Alas, the Gorn Cannon has been mythbusted ... but of course they weren't using Kirk's Alien Super-strong Bamboo so it remains a viable option under the right circumstances.
That is all true, but let us also note the sheer awesomeness of the Rip Helmet Off feat. Roy deliberately exposed himself to direct counterattack by Tarquin ... a very risky maneuver. Almost anything else Roy could have done with his hands would have inflicted more direct damage, but at that point, Roy felt it was worth surrendering another round of direct damage in favor of acquiring the intel he needed to win the fight. That's Leadership indeed ... that's Fighting with More Than Weapons.
Tough break for Roy that his opponent is better at that sort of thing than he is.