It's possible the other ship's window of time wasn't large enough to put the pieces together. For all we know their loop was only a few minutes long.
What I don't get is why they didn't do something like this:
Randomly select whether to go forward or go back in a way based on background radiation or something so you can guarantee it would come back with a different result each loop.
This decision may not get you out of it this loop, but it is guaranteed to save you in the next *few* loops.
I second Timescape as the infinitely rewatchable episode. Picard drawing the smiley face in the warp core breach was awesome.
Of course, if the ship is one kilometer long and the breach would envelop the ship in six hours, the breach should have been noticeably moving.