It was her childhood home as much as it was Bambers.
Both would have known the cupboard intimately
We know this
Disagree with that.
Sheila wouldn't know what went with what amongst the crowded gun cupboard.
She may know how to use the dart board. If there were darts close by.
She also wouldn't have the idea to start shooting everyone in the first place.
Tragically Jeremy left the rifle, magazine and bullets out in the kitchen. Which was rude.
Then Nevill and June didn't put anything away.