According to the last sentence of that post both pilots complied to TCAS:
Luckily (or miraculously
) AI went up and Vistara came down, to be 600 feet away from each other and then flew away safely "clear of conflict".
AI pilot did well by looking for the aircraft that was cleared for the same FL she was passing through, but she could communicate about the possible conflict before that became obvious with TCAS/RA. Once TCAS came on, at least from gif animation above, the separation efforts were about equal (the same delta of speed increase/decrease).
However, I think it is natural to defend the kid that is crying first upon a conflict.