"the recent cuts in immigration & asylum legal aid are leaving many detained without representation… people are languishing in unsafe detention centres because of the inefficiencies and chaos of the Home Office". Her Majesty’s Inspector of Prisons
Disturbance of any of the "vital signs" can indicate serious illness. Use your common sense though, if someone looks obviously unwell or is in great distress, s/he may need urgent medical attention. The following are not in order of priority - the presence of one or more of any of these should prompt you to seek medical advice from a doctor.