Sorry if my point was clumsily given, as I said english is not my first language so my apologies for any possible confusion. What I tried to say is that people leaving key was fortunately pretty rare, and that I encountered only two of them (that I remember) this season. Doesn't means that those two time were great experience, I remember on time was the healer walking on the little welp that wake up the group with the big cristal guy and all (before the two arcane elementals) in Azure Vault. Immediately the tank left, leaving the healer clueless, just knowing that he ruined something. So I of course took the time to explain it that you shouldn't get in range of those welps, we switched on another key that one of the dps had (think it was an academy) and completed the run easy. See, that's the kind of situation that we should be able to avoid, but since people like you don't want to act like competent players and explain to the one just discovering the game, there will always be people walking on those welps.
But again, fortunately that's a pretty rare occurence, sorry if my discours made it sound like it was a regular thing.
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Not the KSM from this seaon (not yet), sorry if that wasn't clear.