Red - This forest with the red tress symbolises enthusiasm and excitement as the one who killed the other man is quite pleased with herself due to the fact that the other woman is now upset and angry with her. She killed him as she saw him and the woman she is fighting with together in bed.
White - This scene and the following ones include many deaths. White usually symbolises purity and death so this is extremely fitting. During the last few scenes of the movie it is mainly white.
Purple / Blue - this is used to convey the strength of those fighting, this can also be seen when the blocks fall down. The colours used enhance the message that is behind the initial actions.