Part 107 UAS pilot reported a switch in the incorrect position caused a flight malfunction.

Narrative

For the maiden flight of the UAV. Pilot In-Command was taxiing the UAV to the established takeoff area Runway XX at approximately XA:20. Upon completion of all checks and arming the aircraft motor; crew began moving the aircraft towards the runway on a southwest heading. The aircraft followed the input of 20% throttle for approximately ~8 feet. At this time; approximately 3 seconds into the taxiing; the motor went full throttle and turned abruptly to the southeast directly for the flight crew/Ground Control Station (GCS) setup. PIC attempted to emergency disarm the motor to the aircraft. PIC was unable to disarm or regain control of the aircraft as it made impact with a safety cone and ultimately a water cooler by the GCS setup area. The aircraft was ultimately disengaged by disconnection of the battery by maintainers on site. The incident in its entirety lasted approximately 8 seconds. It was determined after the mishap that the PIC had begun taxiing with the Toggle Switch engaged for Mission Mode. PIC thought this Toggle Switch was in the Stabilize position. The mode switch was toggled down when it was supposed to be toggled up. The aircraft had engaged the autopilot once 20% throttle was reached and had tracked to its takeoff way point to the southeast of the GCS set up area. It was a determined that the PIC was unable to disarm the aircraft due to a lack of any sort of emergency kill switch on the flight controller.