Syndicate Intelligence Hideout missing Syndicate member for boss fight. Door permanently locked?

The Syndicate member that was missing is Elreon.

I've completed Transportation, Fortification and Intervention hideouts. The only one I have left to do for the challenge is Intelligence. I'm not sure if that has anything to do with it.

It sucks that I have to get a bunch more Intelligence intelligence again now before I can complete the challenge...