1,2,3, red light, green light is a game we learnt about road safety in HK. The rule of the game is for everyone, while rushing to the finishing line needs to freeze immediately upon hearing: "1,2 3, red light, green light". Any person spotted moving after this will be immediately put out of the game.

With DO DO SFX being MTR's unique alarm of closing door, it communicates the message in an amusing and effective way. The cast from all walks of life creates a strong sense of involvement in educating the mass public.