At the mo there probably isn't a used panning and tilting gyrostabilised answer that doesn't cost less than $350k
There is mechanically semi stabilised kit for under $50k that sits in the doorway.
(but still allowing egress in event of emergency m'lord)
As the producer one has to balance the audiences high expectations with affordable kit that allows you to tell the story.
For instance a couple of fixed rigidly mounted cams with wide angle views which are augmented with hand held wobble cam could tell the story.
But it ain't going to look like "Planet Earth" or "Home" in respect to detailed closeups.
I recently used a Red camera with wide lens on a sit in the door mechanically stabilised rig and for closeups used a small hd camera resting on the seat of the Augusta 109. The combo worked well.
Mickjoebill