The matrix is a useful tool, but it is just a beginning. Where it fails is how it is put to use and interpreted. The rare but catastrophic event must be prepared for, in planning, training and equipment. Just because it ranks low in probability does not mean you can dismiss it. A good method for including it in planning is to use the "PACE" acronym for planning: Primary, Alternate, Contingency, Emergency.

Primary: Your primary plan for how you will accomplish your goal, safely.

Alternate: An adjustment to your plan that still allows you to accomplish your primary goals, just in a deferent way.

Contingency: Something goes wrong and requires you to change your goal. Maybe an injury, a shortage of necessary equipment or supplies, or a natural weather event that makes the original goal impossible.

Emergency: Your are in survival mode and trying to get out alive.

Your equipment and supplies must cover all four. Your survival kit is usually for the "Emergency" situation. You must address these four areas while doing your planning, but after doing your risk assessment.