I could be wrong, but I do not believe that this is an option. If you are interested in only running one OS without the need to switch between two, then I would recommend removing safestrap and going with bootstrap.
To remove safestrap you will have to open the safestrap application from the Android OS and choose the uninstall recovery option. Once it is uninstalled successfully you will want to uninstall safestrap from manage applications. Not sure if it is necessary, but once it is removed I would recommend rebooting before installing bootstrap.
Safestrap has the startup screen as a safety measure so that you can get into recovery easily if something were to go wrong with flashing a rom. No button combos to hold, just a simple way to get into recovery. Then again that's why android is so awesome... there is usually more than one way to get something done.