Yeah....... it was ridiculous.
Her floating away is by far the weirdest moment of the series.
As far as the episode goes, I thought it was really good. Though, I do feel like it raised more questions than it answered.
With the locket gone, and Ted (if this episode is definite in its ending) having let go of Robin, what will happen to cause the wedding to go awry?
My theory is that Ted probably has let go of Robin, but can't help but, in a ridiculous last ditch effort, try to get her the one thing she really wanted for the wedding: her mom.
This, leading to the whole locket ordeal being brought to light, and him coming to blows with Barney.