Let's say hypothetically, Ralph is worried because Sheila has got hold of the gun and is ranting and raving, possibly locked in the bathroom so Ralph can't disarm her. She insists she wants to speak to Jeremy. So Ralph goes down stairs to call Jeremy. After speaking briefly with Jeremy he decides to call the doctor or 999 for medical assistance. Before the call is complete he hears noises from upstairs. Bang, bang, bang and June screaming. He drops the reciever and goes upstairs to find June on the floor still alive but bleeding. He crouches down next to her but Sheila comes up behind, bang, bang, bang. He is barely able to stand but tries to get away. Sheila follows him out of the bedroom and shoots at him as he's going down the stairs. He staggers into the kitchen and falls to his knees. He tries to reach the phone but he's too weak. Sheila comes down and tries to shoot him again but the magazine is empty. Ralph pulls himself up on the table and tries to get to the backdoor. She takes the rifle and beats Ralph's head with the butt. He collapses onto a chair his head drops onto the scuttle. Sheila then had time to reload return upstairs to finish off June. Then Return to the kitchen to shoot Ralph 3 more times.
Of course this is just my theory of how it could have happened
