Shot 15 rendered and more glitches @Alan

When I render a scene out with my mesh smoothed it causes problems. For example the torso will detach itself (see image below). When I don't smooth the mesh it seems to render out fine?

When mesh is smoothed

Renders from shot 15 and random glitches!

I find rendering certain points in the scene very useful to get a good idea of how it will look. There was also a glitch in one of my renders (see last render) but the problem has mysteriously gone now.

Here are a few render snapshots from this scene.The king is trying to understand how to fly these 'rocket shapes', we see him go through all the motions!

Upside down - Render

(Smirk) gaining more confidence - Render

Unsure - Render

Almost getting the hang of it - Render

Completely confident - Render

Found a comfortable seat! - Render

Random glitch - Render