Once the meter is filled, go to the Hive and you will see the military attacking the Hive. You can either battle the military and then collect the genetic material that is expelled from the Hive, or you can just avoid the military and just collect the genetic material before the Hive is destroyed. A military disguise can help a lot if you want to avoid combat with them, mind the Hunters however. If you have a military disguise, you can hijack the tanks firing at the hive and control the damage done by the military to the hive. Collect genetic material until the meter fills up completely.