Mettaton just...stands there and watches the waves as they roll down the hallway after the human. That is...that is really not what he expected to be happening here.

A wide grin fills his face. Suddenly, his desperation is gone.

This is going to be simple.

"Keep running, human!" he calls out and throws a few bombs after them. It doesn't matter that most of them are put out by the water Grune summoned. It's the thought that counts.