Tristan doesn't try to get to his feet, staying crouched to the ground and holding on to it for as much purchase as he can. Surely this can't last more than a few seconds more, and trying to run would be hell on his knees and ankles. It's best to wait it out, and not to injure himself before his promised fight at Robena's back and side.

The land [i]is[/i] sick, he realizes, and angry. This is not just an offering gone poorly. For an insult to be met with this... it would be like coming home late, smelling of beer, and your spouse [i]burning down the house[/i] for it. 

Okay, so maybe Pellinore really does need to die then. It's not the answer he wanted, but it was one he needed. 

He keeps one hand on the ground, and one on his bow, ready to draw. Let the other two call the melee. He has no fear of the frontlines, he can just do more damage from here. He now sees this as a job that needs doing, like plucking weeds, let whoever think of him what they may for doing it. 

Let the knights who see the Earth rend itself apart before their lord know whose side they are on, by it, as Tristan has.