Callie was completely unresponsive, almost seeming to be comatose. It wasn't too unbelievable though, considering what he saw. Meanwhile, as it seemed that she was being absorbed by the pod that was there, he noticed the roots.
It wasn't hard to guess wht he needed to do. That thing shouldn't be there.
That room felt oppressive with it's corruption, he could literally feel it in the air.
And that thing was likely the cause. So he needed to kill it.