Collision, "the violent encounter of a moving body with another", is poorly understood in HCI. When we discuss people colliding with the physical artifacts we create, or colliding with each other while using our systems, this is primarily treated as a hazard, something which we should design to avoid. However many other human activities involve situations where deliberate exposure to risk of collision may in fact have positive aspects. In this paper we discuss how the ’risk matrix’, a widely used risk-management tool, which categorizes risks in terms of likelihood and severity, may limit interaction in unintended ways. We discuss reframings of this matrix in relation to design concepts of ’adventure’, ’disempowerment/agency’ and ’consent’. and show that a range of design spaces for collisions exist which may be fruitful to explore.