The portals to the Specimen Chamber meta event disappear before the event ends. I died during the final boss fight, when there are 2 bosses, so I waypointed to Anniogel Encampment, expecting to take the portal back. But the portal was gone, and while I was running the very long way back, I lost participation due to inactivity, and got no rewards for the event despite participating in 99% of it. One of the bosses was at 1% HP and the other boss was healthy when I waypointed.