"The portal wasn't their only way in. It was just the fastest and easiest. I can feel them still trying to push their way in through me, and if I don't stop it in time, they'll break through. They'll be able to create a portal anyway."

He punches in some coordinates.

"As long as I'm here, they'll just keep coming. I'm the door..." His expression hardens with resolve. "And I'm gonna slam it shut. I know just the way to do it, too. I don't know if just dying is enough but I figured out something better, just in case."