In panic one could have made a left turn when they actually wanted a right turn. Tupolev Flight BTS2937 is an example of a deviation of TCAS commands (they followed ATC instructions) and ended with deathof a lot of people. These days all modern aircraft is TCAS equipped but if pilots don't use it and prefer to use rules of the air which was used when aircraft was much much slower and lighter, why bother have TCAS?
Just follow the TCAS commands. Learn from other's mistakes.