I agree, DD was on a runaway bullet train heading for a cliff, and only the power of friendship could have saved him. He had tried to make friends, but the sincerity of those efforts were labeled a sham.
He did , have one trick up his sleeve, however, and when the train was about to go over the cliff he said "Mariners, Mariners, Mariners"
Harmony reluctantly saved him per Harmonys contract with the spirit of pojections, which forces him to appear whenever such sacred word is uttered.