On some systems/drives if it detects an error that is big enough it will reset the carriage. You can here it reading and rescrubbing over and over. That can cause the carriage motor to overwork and burn out. Not sure of this system does that or not. But that would be my guess.
Exactly. And in the worst case the disk itself might disintegrate due to rotational forces, transferring some of those forces to random parts of the interior of the disc drive. Physical and higher sustained speeds and increased temperatures due to many read attempts make that more likely (but still very uncommon). This isn't entirely theoretical, I have a dead drive to prove it, although not from speed running.