History of the energy absorbed by clusters in our synthetic cluster encounter simulations, | δ_E |, as a function of time t. The clusters shown are the eight in total whose ultimate heights above the Plane | z_end | > 350 pc. Each line shows a separate cluster, marked with a different point type and colour. Each point is an encounter between a cluster and a GMC. Large, filled, round points are those where | δ_E | > 1 for a single encounter. The dashed grey line indicates a cumulative | δ_E | value of ten, above which clusters are not found to survive.