Hi Robbie ,
but my (very) hypothetical situation may be V1 145kts, Cargo Fire Warning 146 kts, VR 155kts, smoke in flight deck at 1000' and wishing I was on the ground.
Ah. That's easy to fix.
Since the chance of a Cargo Fire Warning is time dependent and not engine power dependent, then simply delay any take off by about 5 secs (or the same time it would take you to accelerate from V1 to VR.) Thus ensuring that the hypothetical Cargo Fire Warning would now occur below your mid value V1.