The optional for the Mirror Event is "weaken Terran Escort group". But there are no Terran Escorts in the mission. I don't get it.
There are four Satellites on the outer edges of the map, you'll see the blinking lights. Go near them and interact to start uploading a virus that makes the Damaged Staadi ships in phase 2 severely damaged and go down like a sack of potatoes. Keep in mind, unless a group (Alpha, Bravo, Charlie, and Delta) are busy fighting, they'll break formation and go to their specified Satellite and kill the uplink. Think of the map as a large X, the middle is where the Flagship spawns, the inner part is each group, and the tip is each Satellite.