We present a mixed quanturn/classical molecular dynamics study of the pressure driven incorporation of helium into C-60. As a simulation system a C-60 Molecule in a helium gas bath is chosen. From our path sampling molecular dynamics simulations, we clearly identify the preferred insertion mechanism. It involves the opening of 3 C-C bonds of a 6-ring, forming a "window" in the C-60 molecule, which facilitates the incorporation of a helium atom. From a manifold of trajectories, each describing a reaction event, the role of the nonreacting heat bath is elaborated. The approach appears widely applicable to the investigation of reactions in complex systems in general.