User blog comment:MasterSlenderTR/Mettaton vs Betty?/@comment-24530269-20180727135632

he'll rek betty with his legs

As said below, simply because Mettaton is probably getting his metal bump spanked (good luck to Betty to not break her hand in doing so) doesn't mean he'd kick the bucket per se. Possible it is but same goes for the umpteenth unexpected plot twist.