Ah you not got the foot work 
. Foot underneath with keys on your body. Foot out, step back without tripping over. I generally do foot underneath then fast move to the side rather going back. Less risky. It wont activate the tail gate till it knows you are out of the way by the kessy link being broken. That distance. Safety featurfeature.
Sometimes, least in the
Ateca the tailgate rear sensor goes sleepy, about 1 in 100 or so. Use the handle to unlock the car then all back to normal. Kessy the passenger side can go into battery saving mode, pass on whether the Kessy virtual pedal does that as well or the logic gets confused 1% of the time.
The cat does a good job of opening the tailgate when behind. Characterised by a run underneath and beep beep beep. Dah... he's rascal. Helping to unload the shopping.