Letting Saint Tusa and the Dark Zephyr go on a trip might cause the enemies to launch their attack sooner rather than later.
If the Dark Zephyr managed to sniff out the hiding place of the ambushers, then that may be enough to drive them into action.
The departure of a powerful ace mech from the Bluejay Fleet may also lure the cosmopolitans and the native aliens to take advantage of the situation and go on the offensive.
While time was technically on the side of the Bluejay Fleet, there was not much point to waiting around any further.
Fort Rock had come online. While there were still many areas of improvements, the engineers and construction crews had already plucked the low-hanging fruit. They were spending gradually more time on reconstruction efforts that yielded increasingly smaller gains in return.