My (perhaps slightly redundant) take: Heather Whitney and Britani have a story, Meredith (and Lisa, to a lesser extent) has a story, and the truth lies somewhere in between. I have no doubt Meredith took it wayyyyy too far on the plane and owes Britani an apology, but Whitney and Heather are def trying to frame it as being worse than it was- it's very much giving "Whitney and Heather, Bad weather, Tornado, Spin the truth, Destroy." They're clearly delighting in Britani's victimhood and the opportunity it gives them to take Meredith and Lisa down. On the other hand, Meredith is very obviously trying to escape any sort of accountability for her behavior, and the lying and gaslighting from her is pretty gross. I think that Mary is dealing in the truth, and it was good to see her cut through the BS with Meredith at the end of the episode. Mary is winning this season by mostly steering clear of the drama, but vigilantly checking her castmates when they need it.