The way your question is phrased implies that Abraham's Vortex analogy refers to some static "place" that you can get into or out of alignment with. The implication is that you can be literally "knocked" out of that place and go tumbling "down the emotional scale".

It's important to realize that all that the Vortex is, is a convenient model to describe an ever-evolving state of alignment between your "lower" (physical) self and your "higher" self. For further information on this, see: Is Hollywood actually creating a World Catastrophe starting from the USA through its movies?

From that link above, it should be clear that your Broader/Higher Self dominates as far as the attractive power of the two selves is concerned.

And the intention of your Higher Self is always to be seeking for new experience which effectively causes an expansion (for want of a better word) of that self. See: What should we imagine, visualize or believe?

As the Higher Self expands then immediately, by default, the Lower Self is out of alignment i.e. out of the Vortex. It has to now consciously realign with the new vibrational place that the Higher Self has expanded to.

So, really, nothing is "knocking" the Lower Self out of the Vortex, it's just that the Higher Self has now become "bigger" and now the Lower Self has to keep up.

But the really cool part about this expansion is that the by-product of that process of the realignment of that Lower and Higher Self is Joy. For further information, see: Is my rapid expansion the cause of my colds? even though I don’t feel “bad”?

So the intention of the Higher Self creates Experience for the Higher Self, and Joy for the Lower Self.

It's a very clever system :)

So, to sum up, the reason that even someone in the Vortex can attract situations that lead to them being out of the Vortex is because that is the way physical life has been set up. You cannot experience the joy of coming back into the Vortex unless you somehow manage to get yourself out of it, and the vibrational intentions of the Higher Self cause that to happen automatically.

It's a similar idea to food being more enjoyable when you allow yourself to become genuinely hungry first, or a vacation being more enjoyable after a period when you have been working extremely hard, or Christmas being more enjoyable because it comes only once a year instead of every day :)

Variety and contrast are where the fun and excitement of (physical and non-physical) life are...not in stability, even good-feeling stability.