Over time, with Cosmic Expansion, those velocities will increase, and the light from those galaxies will continue to red-shift until we cannot see them above the 3-degree Kelvin Cosmic Microwave Background Radiation.
Because Cosmic Expansion is measured by the relative red shift of distant astronomical objects — and the red shift appears to show that the furthest objects in all directions are red-shifting away from us — and therefore accelerating away from us, the same effect would be true if everything in all directions were "falling" away from us into a huge gravitational well. Dark Flow gives us the direction into the deepest part of that well.
For Coma Cluster galaxies, that velocity computes to a significant Lorentz contraction factor: A one million mile ruler traveling 2.2 million miles an hour lengthwise in the direction of the Dark Flow would be contracted to 999,995 miles long — 5 miles shorter to an observer at rest.
So, could we all be inside the event horizon of an incredibly intense black hole and still falling towards its singularity point?
If we are falling into the bottom of a prior universe's blackhole — our relative time dilation factor will increase towards infinity as we approach the singularity point as relative velocity approaches a significant fraction of the speed of light. Relative time dilation slows our clock to a near stop. So it gets very, very, dark and very, very, cold down there in the very, very, distant future, which is why the deep sky today is really, really, dark, beyond the Cosmic Microwave Background Radiation.
And the Big Bang?
That's what happens when a universe worth of our energy and matter slips through the event horizon of a prior universe's blackhole and emerges from zero spatial dimensions at zero time, as the energy "snaps" — "relaxes" — "expands" — "coalesces" into our dimensional space and time which we humans believe wraps around and through us.
And the post Big Bang blackholes that are formed by stellar implosion, dark matter implosion, and found at the cores of galaxies and quasars?
Well, those gravitational fields represent localized surfaces of infinite relative time dilation created after the Big Bang. Think of them as patches of space-time turbulence which connect to the same time surface that all objects in our Universe bubble will ultimately arrive at in the direction of the Dark Flow, except scattered backwards spatially from the End-of-Observable-Time.
Localized blackholes are short cuts from now to the End-of-Observable-Time in our Universe.
While they are all points in the same observable-time "surface", they have different spatial locations and gravitational strengths, evidenced by the different sizes of the Schwarzschild radius of each local blackhole. When an object with mass and energy crosses the event horizon of a local blackhole — it is actually accelerating past the speed of light in our universe, and becomes unobservable in our space-time because it's velocity instantaneously transforms into some non-spatial dimension set orthogonal to our space-time, leaving behind its mass energy value in our universe as an increase in the gravitational field of the local black-hole with a proportional increase in its Schwarzschild radius.
The gravitational field of a blackhole is the "echo" of matter and energy that has "entered" non-observable space-time for any observer outside of the Schwarzchild radius.
If the Big Bang is the "scatter" as spatial dimensions emerge — then post Big Bang black holes, of all different masses and ages, are part of the "gather" as objects accelerate and become unobservable into higher dimensions, effectively "leaving" our universe while conserving matter, energy, and information in our universe as an increment to the gravitational field of a point singularity.
To put it in perspective, we are in the Dark Flow from zero time dilation to infinite time dilation, from zero initial velocity to speed of light, from zero spatial dimensions to non-spatial dimensions.
What could be driving the Dark Flow into the future is a "massive" point singularity created by the previous universe, whose dimension set is orthogonal to our space-time. We are somewhere inside its "Schwarzchild radius" for its "speed-of-light", but we have not yet arrived at its point singularity where all of its dimensions vanish. That point singularity could "co-exist" in the hypervolume bounded by our End-of-Observable Time Surface, assuming that gravity is the common book keeping system for the conservation of energy, matter, and information across all universes and across all emerging dimension sets.