When Kirsten and Cameron first arrive at the rave location Cameron locks his car using the remote. When they leave Kirsten goes directly to the car and opens the unlocked car door without Cameron's use of the remote.
During Kirsten's second stitch into Lisa's memories she sees Raff physically open Lisa's mouth to force her to take the drugs. The masseter (the main jaw muscle) is one of the strongest muscles in the human body. When all the jaw muscles work together they can keep the mouth closed with the force up to 200lbs at the molars. Therefore, forcing open someone's mouth would be significantly more difficult than shown, if even possible.