Not really sure, but you might want to try open url in new window instead of goto url?
Open URL in new window
Navigate to a given URL in a new window (or tab if the browser settings override). This continues to run the HTML5 game in the old window or tab.
Go to URL
Navigate to a given URL. Note this uses the same window/tab as is showing the HTML5 game, so this action will end the game. The Target can be used to select which frame to redirect, which is only useful if the game is displayed within a frame (e.g. an iframe embed), and the frame has permission to redirect the parent frame (i.e. it is not sandboxed). Possible targets are:
Self: redirect only the frame that is currently showing the game.
Parent: redirect the parent frame.
Top: redirect the top level frame (only different to the parent if more than one frame is used)