Below v1 ... I'll stick my neck out and say, ABORT! Controllers only cancel a takeoff clearance when there is an immediate threat to safety. What justification is there to use emergency authority to continue?

If there's a runway incursion, or I've lined up on a runway with a bulldozer at mid field, or pilot just made a pirep of 40 knots loss of airspeed off the parallel runway, there's probably some very good reason for Tower to cancel the clearance.

From the right seat ... it is the Captain's jet obviously.