It's the first step when arriving the scene , contains 5 things every paramedic should be aware of and done first. 1- Scene safety . Your safety is your top priority! Before going to the scene and involve in it you should determine whether the scene is completely safe or not. 2- NOI , MOI You should know the case you will take if it's Medical ( Nature of illness ) or Trauma ( Mechanism of injury ) It's important to build the differential diagnosis and to start the evaluation and physical examination based on its type. 3- Number of patients. You should know the number of patients to decide who has the top priority and if you need additional resources to complete your mission. 4- Additional resources. Based on the scene safety and the number of patients you will decide if you need any assistance , from police or firefighters or any other departments that will help you. 5- Determine C-Collar If the patient was suspected to have spinal injury , you should put C-Collar to him , to stabilize and minimize the motion of his nick to protect his spinal cord from damage.