The pathologist said Neville would have had difficulty speaking from his teeth, neck, jaw and larynx injuries.
This means Neville phoned Jeremy before his non bullet injuries. The phone suddenly going dead suggests Sheila put her hand over the phone. Neville would automatically put the phone on the hook himself.
Would Sheila really be able to win a fight with Neville, even if Neville had been shot in the torso ? Sheila did not have a mark on her.