The officer will keep his/her hands above their duty belt as they approach your car. Some officers will have their hand on their weapon while it’s in the holster, this is a safety tactic that the officer is trained to do when in the academy. This allows the officer to have a quicker draw of his/her weapon should he/she need to use deadly force.
Police officers are not taught to injure you, they are taught to aim center mass in order to neutralize the subject when using deadly force. The reason for this is to ensure that the person isn’t able to cause physical harm to the officer or anyone nearby. Should an officer injure the suspect, the suspect may continue to use deadly actions and harm others including the officer. Keep in mind, this is only when the officer has probable cause to use deadly force.
The officer may call for backup if there are more than two passengers in the vehicle, at the officer’s discretion. This is done for safety reasons.