[L3n1n]

You found correct event, but you need to know correct argument: 10 is GuildBanker. There is example for you:

local f = CreateFrame("Frame")
f:RegisterEvent("PLAYER_INTERACTION_MANAGER_FRAME_SHOW")
f:SetScript("OnEvent", function(self, event, arg)
    if arg == 10 then
        print('gbank has been opened')
    end
end)