What is the test for establishing that there is a danger to public safety in a hospital?

The inquiry must be whether, as a matter of fact in the case under consideration, there are factors in the circumstances which, in relation to the ordinary and usual state of affairs the permanent safeguards for which are not determinable at common law, are of such exceptional or special nature that, when carefully examined in the context of all of the circumstances, they should be taken into account to determine whether they have created a danger to the public beyond such as are usual to normal operations, and for which ad hoc safeguards must be provided. In this I follow the succinct statement of Johnson J.A. in Weiss v. Larson et al at p. 70. If the danger is, or ought reasonably to be, apparent from normal operations, it does not arise from exceptional or special circumstances.