(t=0) is being used to try to describe some fictitious -- to me -- time around and/or before the big bang of the Big Bang Theory. It, t=0 REALTIME NOW (t=0), has nothing to do with that Horizon (well almost nothing to do with it being all here-now 0-point center-point, infinite '0'. between horizons), which I term the "closed up collapsed cosmological constant (/\) Planck (Big Crunch) (Big Bang) 'Mirror Event Horizon' (t='1' (='Unity') rather than t='0' (='Infinity' (='Chaos'))(a fundamental binary base2)) of an infinity of universe (u) horizons (horizons of universe (u))!" Altogether, also known as an "Infinite MULTIVERSE Universe (U)."
"Entangled, entangling, spontaneously concurrent (t=0) REALTIME NOW (t=0) instantaneous moment" has to do with the horizon, and all the horizons, of the predicted breakdowns on the one hand, and buildups on the other hand, of relativity! The disappearance of relativity (t=+1 (into coordinate point SPACETIME's past histories (-->>))) on the one hand, and the appearance of relativity (t=-1 (from SPACETIME's coordinate point future histories (<<--))) on the other!
If you can think about and realize the above, you must realize there can be no such thing as "time dilation" except as it refers to the constant of the speed of light stretching across distances . . . long and longer distances . . . slowly, and ever more slowly . . . going from being the ceiling fastest of all possible speeds local relative to the slowest of all possible speeds "at a distance" (a "spooky action at a distance").