What is the common intention of a group of people who jointly take part in a wrongful act?

My colleague states that, in the cases decided under both the Civil Code of Québec and the Civil Code of Lower Canada, the persons who had jointly taken part in a wrongful act had “shared a common, albeit sometimes tacit, intention, a factor that is sorely lacking in the instant cases” (para. 59). Yet the cases he cites (at paras. 47 et seq.) concerned groups whose tacit intention was established on the basis of their having participated in a dangerous activity that had resulted in injury. In most of those cases, there had been no prior agreement between or preparation by the members of the group. I need only cite the example of the drivers who spontaneously participated in an impromptu car race (Gagné) or that of the group of children throwing stones for fun (D’Allaire v. Trépanier, [1961] C.S. 619 (Que.)). Therefore, as regards the intention that must be shared by persons who jointly take part in a wrongful act, the cases in question are fully applicable to the instant cases, in which groups of persons participated spontaneously in the destruction of vehicles.