In a personal injury action, in what circumstances will counsel argue that a point at first seems key?

We have no criticism of either counsel. Sometimes a point at first seems key, and later seems not as it first seems. The words of Viscount Radcliffe in David v. Cader, [1963] 3 All E.R. 579 at p. 583 (as quoted in Stagman v. Hamm, 1984 CanLII 2565 (SK CA), [1984] 5 W.W.R. 148 at p. 162) apply: "Useful as the argument of preliminary issues can be when their determination can safely be foreseen as conclusive of the whole action in which they arise, experience shows that very great care is needed in the selection of the proper occasion for allowing such procedure. Otherwise the hoped-for shortening of proceedings and savings of costs may prove in the end to have the contrary effect to that which is intended. This, unfortunately, is one of such cases."