Chaps, RTFQ. The question says FAILURE at V1 +/- 10kts, not action. Since the mid 90s V1 has been redefined, it is no longer a failure speed or a decision speed it is an action speed. Simple!
"The maximum speed in the takeoff at which the pilot must TAKE THE FIRST ACTION to stop the airplane within the accelerate/stop distance.”
Thus any failure must occur some time before V1 for you to safely decide and then take action prior to or at V1.
Of interest the B777 'ENG FAIL' alert on the PFD is inhibited 6 knots before V1, I think those clever chaps at Boeing are trying to tell us something!