The first attempt to link up with the friendly space carriers went badly when they were intercepted and destroyed. Considering the us vs them numbers, the material loss of even 2 ARMD carriers is substantial. Making another run to the friendly fleet would have opened them to ambush again- which is even dumber IMO.
What was the situation then.
1. The flagship is under attack by massive numbers of strike craft while grounded. There is a land battle in the civilian city and no hope for reinforcements from both terrestrial forces or the space fleet.
2. Fleet in space has been ambushed and has suffered major losses against unknown number of hostiles.
3. Flagship main propulsion is damaged and floating away
. Secondary drive system is functional but inadequate to escape from hostiles.
4. Enemy has targeted only the flagship although direct damage done is minimal. Suspect that the objective is capture instead of destruction of SDF-1. With that said, defense forces have proven to be adequate in repelling the attack although there is a logical limit to their combat endurance.
5. Main weapon has discharged, unknown when it is possible to fire again. Even if they could fire, the main gun will be the primary target for strikecraft attack in order to disable it.
What are options remaining for escape because the relentless beating will likely kill all their pilots and end with the capture of the SDF-1? Go to another country for support? Not funny when it appears that the enemy just keeps coming. Make another break for space? Unlikely. Or bait the enemy strike craft away from their carriers and jump to friendly space [like the moon base] where they can link up with the fleet and find the time and space to deal with the hostiles through diplomacy or military force.
Personally, I don't like the last option for the same reason as the last 2 rogue instances this damned piece of second-hand junk messed up and went wild. Too many unknown variables and too much pressure to come up with something else.
Put it this way, the last gambit is exactly what it is- something done after the other options were literally shot down by the zentradi