Hard to pin down exactly what his thought process was at that point.. In that van, there must have been some sort of instrument he could use as a shovel, he had a certain amount of time on his side.. But that would require clear and logical thinking, and considering his public behaviour up to that point, logic and clarity were not operative.
And his rage. That must have been overwhelming, really.. how much trouble and unpleasant scrutiny she had bought upon him, him, he, who was above all this little vloggy stuff and hard work and was a warrior for nature and all that soft stuff.
I can see him stomping off, full of fury, with that peculiar flatfooted walk (which is why I doubt the App trail story, flat feet ) , not even stopping to pay respect, or to even cover up his own crime, but a cavalier 'up yours' to the world. .
Because that is what it was. Leaving her out there, exposed, subject to animal curiosity, the weather, the dust, the difficulty of her parents finding her.. a big middle finger to it all.