I thought it was Live or Die, but not in the context if Ashoka should live or die - but more would she let her opponent live or die. She has been very aggresive in battles lately, similar to Anakin near the end of the prequels. Look at her clone wars flashback that Anakin didn't know about. She was slicing foes up left and right with no remorse. So was she going to let Anakin live (good side) or die (dark side). She's been teetering the edge of going down the same dark path as Anakin. This seemed to be a place where she needed to decide who she was going to be, and in the end chose to let Anakin live thus repelling the dark side. At least thats how I took it.I have no idea what message Anakin was trying to get across but it looked very cool.
I think it was simply to make a choice whether to live or die. But I'm terrible at interpreting this stuff.
It still could be in the context of Ahsoka if she follows Anakin's path, but just not in a literal sense. Obi-wan: "He ceased to be Anakin Skywalker and became Darth Vader. When that happened, the good man who was your father was destroyed. So what I told you was true, from a certain point of view."