A guide assembly for an endoscope is provided. An inflatable balloon is disposed at a distal end of a tubular housing of the guide assembly for mounting on the endoscope. A flow channel is formed in the tubular housing, for supply of fluid to the balloon and suction of fluid. An end sleeve is disposed at a proximal end of the flow channel, for connection with a balloon control device. A receiving port connects an external syringe of a male tapered shape to the flow channel in place of the balloon control device. A port adapter is convertible from a normal mode toward an emergency mode. In the normal mode, the receiving port is internally contained to set the end sleeve. In the emergency mode, the end sleeve is withdrawn by partial elimination, to uncover the receiving port.
