Click, or tap, if you are stuck at the required clearance screen, click or tap the lock. then wait, and dont click/tap anything else. What is the Locked Box Test? The Locked Box Test is an informal guideline used to determine an object's most appropriate Containment Class. It goes like this: If you lock it in a box, leave it alone, and nothing bad will happen, then it's probably Safe. If you lock it in a box, leave it alone, and you're not entirely sure what will happen, then it's probably Euclid. If you lock it in a box, leave it alone, and it easily escapes, then it's probably Keter. If it existed, and it doesn't exist now, or has no anomalous properties now, it's Neutralized.