Prima facie, Chris has committed battery against Bill and trespass to his goods (in using the phone) and conversion (in not giving the phone back). Dr Xog appears to have committed a battery to both Bill and Zelda. Chris would plead defence of another (presumably from perceived reckless driving). This will have the same elements as defence of self, and thus requires both necessity and proportion. Of course, it seems that Chris made a mistake about the threat posed by the car to Bill; but the court might accept that the defence is available on making a reasonable mistake about the threat posed by analogy with Ashley v CC of Sussex. As to the use of the phone, Bill might have consented to making the call but not to the deprivation of the phone. Dr Xog would plead involuntariness in the sense that he did not mean to sneeze – this being similar to the spasm example discussed in the textbook. Alternatively, he might plead inevitable accident – although this does not seem as convincing as involuntariness. Zelda would also want to plead defence of another, but it appears that there were no reasonable grounds for her actions. Neither mistake nor insanity would be a defence.