MMR and tanking

Hi, apologies if these questions have been answered elsewhere but wanted to ask a few things.

  1. Does A player have a single MMR that is shared across all the PvP events (lightning rounds, best there is, danger room, etc.) or is there a separate MMR for each event?

  2. If a player starts tanking immediately, can they lower their MMR below the starting value to get even higher points from matches?

C) Does a tanking team need to win a match for other players to see them? Or will retiring/losing the match produce the same results?

  1. MMR is shared between all PVP tournaments.

  2. MMR does not affect the points you get from matches, only what opponents you see in the tournaments.

  3. Used to be a retreat will work, with latest patch they changed it to be the last team you WON a match with.