I currently work on the E75 & E95, they are definitely not the best designed door! The arming lever & operating handle are in the same area and operate the same way (lift arming lever up to disarm & operating handle up to open).
At the moment to arm the door we lift the plastic flap & grab both the vent flap handle & arming lever together & push it down (door is now armed) to disarm we lift the plastic cover & graph both vent flap handle & arming lever & pull up (door disarmed) we then grab operating handle & pull up & push door out. Sounds confusing but I suppose working on it day in day out means you get thr hang of it!