The concept of three simultaneous attacks is done so that Sango can test out three theories concerning the use of the time reversal ability.
The first theory is to discern the time limit for the use of the time reversal ability. The second is so that he can understand precisely how fast Ruby has become. This is vital information that is essential for what the flow of the battle will turn out to be.
The third and also the most important aspect that needs to be known if Sango has the intention to put an end to the PVP.
Sango has to know if at all time reversal is the ability Ruby is making use of. He had guessed it to be so, but he shouldn't be too hasty to rest his assumption on that alone.
Abilities come in different forms and effects, some with similarities to others, while others have no similarities at all.