What you need to do is get a func_render to make the func_breakable dissapear and another to make the Func_door to appear, once done then when you go to trigger the func_render, say you walk up to the door and press use to open it, it will trigger a multi_manager that will trigger the door to open, then 10 seconds after(ex.) make the multi-manager trigger the two Func_render, (which will make the Func_door dissapear and the Func_breakable appear, Then make the multimanager also trigger the func_breakable to explode(say 12 sec. after the multimanager was first triggered), And thats that. easy as pie.