DLA TO PIP assessment - Mentally unstable

Hello folks 

First time poster and I’m looking some general advice regarding a DLA to PIP change over. Been on DLA for 10 plus years and any reviews were always paper based after the initial medical. 
I sent in my application form about 9 weeks ago and I received my Capita initial claim leaflet saying that I may be called to a medical. I have been doing lots of research and I’m fully aware of the underhand methods that Capita go to to deny claimants. 
Current medical conditions. 
Anti social personality disorder (mentally and emotionally unstable, history of violence) 
Large sliding hiatus hernia (mimics heart attacks) 
Meniscus tear in left knee requiring surgery. 
Temporal lobe epilepsy. 
My right shoulder dislocates on a regular basis and I have limited range of movement due to scar tissue in the tendons. 
Meniere disease (vertigo, hearing loss, balance instability) 
Disc damage in my lower back which also causes sciatica. 
So basically if I was a horse I would have been shot a long time ago lol 
I searched the internet and completed the form in as much detail as possible stating how I was restricted for most sections due to the above conditions and then got my mum (my carer) to complete the further info section detailing more or less what I had already said in the form. 
I’m on about 18 different tablets a day as well including anti psychotics, anti seizure meds etc which all have their own lovely side effects. 
So a day later I received a letter to say I’ve an assessment this coming Monday. I checked the dates and the initial claim letter was sent and a day later an assessment letter was sent. So none of my care givers have been contacted and I’m guessing that my questionnaire hasn’t even been read. 
I read through the gov.uk guidelines and as far as I can see none of the guidelines have been followed and it’s just basically everybody has to have an assessment approach. So now what do I do? I’m now in a condundrum where if I ring Capita and say I am mentally unstable and if I have a medical it might not end well, they could misconstrue that as a threat (my psychiatrist wouldn’t even put me forward for group therapy as I have a very low threshold for frustration and getting questioned for 90 minutes I’m guessing won’t go well) I would think that a paper based review would be the best way to proceed but how do I get them to do that? Would they really try and force me to have a medical when it states in their guidelines about staff safety and psychological welfare of the claimant, as even getting the letter today has caused me to be in rage mode all day.
I can contact my GP and get access to my medical files to support a paper based review but that can take 21-40 days. 

Any help or advice greatly appreciated 

Thanks

Ch0p