The takeoff data isn't just calculated to get you airborne in the TODA, its also pretty damn important to clear obstacles as well in the takeoff path Engine out.
Therefore if I'm commencing my third attempt to takeoff someway down the runway with now invalid data I'm going to:-
1/ Vacate the runway and taxy back to the holding point
and 2/ re do the before takeoff checklist.
We are not paid to "guess"