Xiao Zhong’s magic show got too many weaknesses.
1. If u see probably, the box could be open from backside (door hinges).
2. U could observe the moving of hands upwards (while the curtain was close), indicated the change of the person in holding the curtain.
3. There was too much time for the assistant to enter the box from behind (Xiao Zhong’s was holding the curtain for quite a long time), although his ‘fast’ appearance had created the illusions quite successfully.
Of course, the weaknesses are only obvious in video…