Sitting ildly,
"It is a critical call. "
And you are right. It is! But imagine this scenario. Your V1 is 140. At 138 knots, you have a master warning for an engine fire. Both you and the FO will undoubtly take at least a quick peak at the screen to see the failure. By that time, you will be already above V1. Your initial action of pulling the throttles back will come 'late' as defined by NOT having them pulled by 140 knots (V1) in your case.
The closer you get to the V1 value itself, the less time you have to decide and initiate the abort. That is again why many carriers have you call out V1 at V1 - 5kts. That is a good value in which if you catch your engine fire at 134 knots, there's a good chance you can have the throttles to idle by 140 knots (V1) and now be "legal" (at least on paper) to stop.
Anyone entertaining a stop at V1 needs to keep in mind the law of kinetic energy. It is equal to mass times velocity squared. Your energy increases at the square value of your speed. That graph shoots off the charts at high speed values. You better have pulled the throttles back at V1 and not a knot late. There is what's written on paper, and then there's real world as you watch the runway go right by you as you attempt to stop. A RJ crew tried a high speed abort on a 6,300 ft runway. EMAS saved them. Otherwise, had that not been there, they would have been a smoking hole at the bottom of a cliff.