Never been to Briar Hill specifically but I've spent a fair bit of time in old institutional buildings here in Suffolk and there's always something about the east or north-facing wings that seems to hold onto whatever happened there. Whether that's psychological or something more, I genuinely don't know.
What kind of activity are you picking up in the east wing? Is it more of a residual thing - same sounds repeating, that sort of atmosphere - or are you getting responses, things that feel intelligent and reactive?
I ask because I've got some experience with haunted objects that were recovered from old sanitariums and the energy those places seem to leave on physical items is quite distinct. Makes me wonder whether the building itself is acting like one big haunted object in a way.
Would love to hear more detail from anyone who's actually been inside. Are there any investigators who've done overnight sessions there and documented anything properly?