Ultranova Dumb boombox
So....Mr. @Dumb. Not happening. That is WAY too OP. But...I'm not gonna retcon you completely. Instead, the device caused significant gravitational damage to the moon it was orbiting and caused minor orbital shifts.
Now back to the story. (This is apparently becoming a thing now.)
As Hans and Erika round a corner in the dank dimly-lit engine sections, they find themselves in a large room and then the assigned R-UPA enter the area from another corridor. Shouts of surprise fill the room before one of the overhead bulbs flares up and explodes dramatically and a voice cries "Knock it off!"
Cautiously, both groups turn towards the speaker, who is revealed to be the same grungy man that gave Hans the paper earlier. He smirks at them and crosses his arms.
"So here we got two groups of fartbrains. You guys are NOT subtle. In fact the only reason you weren't arrested when you docked is that we managed to keep Port Security busy elsewhere. You can think of us as a sort of underground resistance. And you can think of us as your ticket to Taros. Without us, you'll never even make it off the station without getting noticed by the Big Man! Now are you going to listen or are you going to be stupid and try to go it alone? If you'd like to be sensible for once, then get your buddies and show up at Hangar 16-B tomorrow at 1500."
Then the man turns and stalks off into the shadows.
Back at the hyperspace passage, the Imperial fleet begins to weaken and falter. Just before the line seems to break, however, alerts begin to light up on both sides of the fleet as something absolutely massive emerges from the gate. A Trisagion class Super Dreadnought, and its escorts!
The GSR forces are driven back in a storm of turbolaser bolts as the Imperial crew members go wild, cheering and celebrating their salvation. For even corrupted and tainted as it is by the Shadow, the Imperium's military might may not be gainsaid while the Circled Star yet adorns even one ship hull. For the commander of the defense forces, things are very different. He quietly slips away from the jubilant crew and comms the captain of the captain of the Super Dreadnought. His voice is solemn and serious as he asks "Is this it?"
The captain nods, his face grim. "We were all that could be spared. The Forge is offline for the moment, and the fleets are scattered far and wide. All of the rest is frigates and cruisers, and those are tied up policing all the damn civilian ships we've been getting for the last week. Add in that the Rift generators are almost out of power..."
The commander finishes the sentence, turning away, weary and aged. "And we're on our own."
"Indeed. We must hold the gate against all comers until the fleets return, lest ruin and fire fall upon the Throneworld and its people. We are the defenders of the people..."
"...And our bodies the walls of the kingdom."
The captain nods, and then the transmission cuts out as the commander goes to roust his crew out of their party and get the salvage yards going.
And at the edge of the Imperium, the rift generators sputter...
...and fail.