Final answer:
When an adult choking victim becomes unresponsive, call for help immediately and begin CPR after checking for responsiveness and breathing.
Step-by-step explanation:
If an adult choking victim becomes unresponsive after you have already performed 7 abdominal thrusts and laid them on the floor, the next step you should take is to: Call for help. Once help is on the way or others are alerted to call emergency services, you should immediately commence with CPR, checking for responsiveness and breathing first. It is important to follow the correct steps when rendering first aid to avoid causing further injury to the victim, such as broken ribs or damage to internal organs from improper application of CPR techniques. Professional training in CPR is highly recommended for everyone as it can significantly improve the chances of survival for someone who is unresponsive due to choking or any other cause of cardiac arrest.