Now your getting silly.
It is a big house, maybe she was able to avoid her or by locking herself in a room for safety. Read my take on the box room. You can find it using the search facility. Maybe she was shot a few times anyway. We cannot know. Maybe she was able to evade her because SC ran out of Ammunition.
I do not know she may have been being ultra defensive because of pain or shock. She may have shouldered a weapon ready to shoot when she heard voices. We cannot know.
The Box Room
This room as a sanctuary has unique qualities. Firstly, it has two exit/entry points. If pursued via one you could duck out through another. Both doors could be lockable to say, prevent anyone from the twin’s room entering and disturbing sleep. It was large but without photographs we do not know how much space there was or whether there were objects inside you could hide behind.
Perhaps the most important feature was the positioning and opening direction of the doors. No one can enter at either point without being fully exposed. There is no cover from a door. If someone is in there with a loaded weapon (Say a rifle or shotgun) you would be a sitting duck upon entry.
It is possible that Sheila was in the box room in the early stages. Nevill and June dare not enter. She may have been saying stuff such as “You will not take my boys away from me” If you try I will shoot you. In such circumstances Nevill and June could have descended to the kitchen to phone JB. It also meant that June was aware that it provided a place of relative safety.
It is possible that an uninjured or lightly wounded June could have remained in the box room for an extended period of time.
It is therefore possible for June to be alive and not responding to police requests for actions and was still alive when the TFG made entry.
We cannot know what events took place after JB left and the TFG entry but there are lots of possibilities.