Exactly, why would they have suddenly changed course the first time through?
Indeed, the argument they should
have made is that these time loops which end up with the E-D destroyed are not particularly dangerous, because the events are always reset and nobody gets killed - but they are damn annoying, and so the heroes should press forward and face the time loop for as many times as it takes for them to render it harmless, not just to themselves but to other star travelers as well. The mission of the ship is not to survive, but to accomplish various mission goals arising from standing or specific orders. Survival is optional, and in this case doesn't seem to be particularly unlikely, either.
In other words, "Shut up, Worf, you are being a coward again!".