If he was in a flight mode using the AltHold controller (AltHold, Loiter esc) the motors may not spin until mid throttle but I would agree there is probably something off with the radio calibration.
I agree with you correct me if I’m not true
I think In ESC calibration mode flight mode is not affect throttle stick
I’m always calibrate my ESCs in stabilize
After watching that video again I realize he was actually attempting to do an ESC calibration with the props on. 1st mistake as you noted. Then for some reason he throttled up the craft after the calibration was done. Attempting to fly in the laundry room?
You are right about the flight mode it is not considered during ESC calibration. I didn’t realize he was attempting a ESC calibration under those dangerous conditions.
Note: reaching thru props to press the safety switch while the transmitter is at full throttle is a very foolish thing to do…