Hi Ht,
Have a look at our PIP guide, towards the back is a section that tells you what to expect from the face2face assessment. Do not expect it to be a 'medical' per se, there will be no in depth examination and questions are often only obliquely related to the questions on the PIP2 form.
You should consider that the assessment starts from when you arrive outside the assessment centre and continues until you leave.
PIP help for claimants