It would have had to have been soon too...

Of course this also meant that the Echo trigger had to have been after the actual fall of the Keeper too, by days at least if you can imagine trying to go from Silvertear Lake to Ul'dah would have taken a bit of time. When your echo occurs, Warburton and Ascilia have already arrived. D=

So if it wasn't the exact moment of the Keeper's fall to trigger the echo... then what was it?