Systems engineering (SE) addresses the six interrogatives who, what, where, when, why, and how. Architecture artifacts provide static descriptions addressing the first three interrogatives: who, what, and where. Executable architectures add the interrogative when, allowing for a dynamic evaluation of system performance. We propose an approach that takes the evaluation process further by addressing the final interrogatives why and how: embedding executable system architectures into an executable context (EC), creating a scenario in which to evaluate the system in the operational role and evaluate mission effectiveness. Combining existing contributions into an executable context simulation framework allows for a holistic evaluation of systems that are models based on engineering specifications in operationally relevant contexts. We have successfully implemented a prototype to demonstrate feasibility and usefulness of this recommended new approach.