So I just ran through this instance again and I think I have a solution. First, make sure you use auto when facing the rhino as it kills it faster giving you more hp for the next part. Second, the chameleon seems to be immune to damage from the mysteries so select the dog and hit the it with as many of the mysteries as possible so it is out of the way, then finish by not using any mysteries to finish off the chameleon.

If someone can double check these results that would be grate.