It could be a flashback, but it also makes sense for it to be connected to Logain, based on the posts here. With a high number of Reds being present, that also makes sense and supports this theory. As well as the Warder crying adds to this.
This is definitely more mysterious than the Nynaeve push, but when I watched it, I just thought they were the bodies of the Emond's Fielders after Winternight. It looks like they are going to make Logain a bigger character, but we will see what happens. The Wheel weaves as the Wheel wills.