I believe JB and JM continued to make love until the end.
The point is moot as there is no evidence that Nevill managed to do any more than fend off the final savage blows of his attacker. He didn't flee downstairs because he felt like fighting after he was shot and was simply left with no choice once he was cornered in the kitchen.
JM did not mention seeing any marks or bruises (despite her supposedly being hellbent on framing JB) and thanks to the idiots 2002 appeal, (ground 13 para 445) we know that Ann Eaton observed his hands reporting no scratches ( despite her supposedly being hell bent on framing JB )
the fact that at no point during the trial was any evidence led from any witness, nor any witness cross-examined, to establish or suggest that the appellant had at any material time had any scars or scratches on his hands. Indeed, on the hand-written postcard note from Ann Eaton (CAE/4) which was disclosed at trial, the entry for the 8 August recorded "No scratches on his hands - no shaking at all"The only caveat being that JB was probably wearing gloves whereas Sheila was certainly not.