Forum:Gorz and "cards your opponent controls"

If your opponent Summons Fire Trooper and activates its effect, since it's no longer on the field (and thus under your opponent's control) can you drop Gorz the Emissary of Darkness or not? A similar question applies to if your opponent gets a one-shot burn card off the field with Emergency Provisions. Thanks for your help. Battlemaniac (talk • contribs) 13:58, June 15, 2013 (UTC)