Stuck in Grand Phylactery L3 Vaal Temple

Killed all the monsters, but the doors won't open. It looks like there is a boss that should activate, but it hasn't. I don't see anything to interact with.

Update: I portaled out, went back to the room, and there was a soul core infuser or something to interact with that, when a soul core was placed inside, activated the boss. This was not there the first time, and I had picked up the sole core reward in the room before.

Same issue. I cannot interact with the Soul Core Infuser. I portaled out and went back, no change. Still cannot interact with the infuser.

Update: Get behind the statue, then you can interact.