What action should be taken immediately after the aircraft has stopped?

The recommended action of checking outside conditions and ensuring that the slide is armed after the aircraft has stopped is critical for passenger safety. This step is essential because it allows the crew to assess the environment outside the aircraft before taking further actions. Conditions such as fire, smoke, or other hazards can determine whether it's safe to open the cabin door or proceed with evacuation.

Arming the slide is also crucial because it prepares the evacuation system for use, ensuring that it can be deployed quickly if an emergency arises. This check is a part of standard operating procedures to ensure that the safety of passengers and crew is prioritized immediately after the aircraft has landed.

Other actions like opening the cabin door or evacuating passengers may seem immediate, but they can only be conducted safely after confirming that the external environment is secure. Preparing for landing procedures typically relates to actions taken while still in flight, not after the aircraft has stopped. Thus, checking the outside conditions and ensuring the aircraft systems are ready is the proper immediate reaction after landing.