You should be ready to take control of the drone at any point during a mission in case of an emergency. The quickest way to take control is to flip the flight mode switch out of P (to sport or another mode) or use the hardware pause button on the remote controller. Either option will instantly pause the mission and immediately give you control of the drone. You can also tap the pause button on the screen or hold down the RTH button on the remote controller.
Important: Some remote controllers, such as the Mavic Mini, do not have a flight mode switch or a pause button. In this case, you can press the RTH button and once RTH activates, press it again to deactivate RTH and take control.