At 46:50 Poirot reaffirms that Christopher Davidson is the murderer by tossing a statue at him. Davidson catches the statue with his left hand proving he was left-handed. Catching with your dominant hand is often not the case as many people who grew up playing baseball or cricket will use their non-dominant hand to do a single-handed catch. In this instance, it would be unclear which of Davidson's hands is actually his dominant without further investigation.
At 46min:50 sec, Poirot leaves the radio studio through the left brass door and the camera on a tripod as well as the cameraman's reflection is seen on the closed right brass door.