I do not see any scenario in which missing a milestone can be considered a success. I understand that a milestone not being met because “something came up” with respect to safety may seem like a blessing in disguise. But truthfully, missing a milestone because of an oversight or lack of due diligence earlier on in the process (initialization and planning) does not somehow make the missing of the milestone a success. Missed milestones can mean the death of a project. Thats not to say if an obvious hazard is discovered, it should be ignored to meet a milestone, rather better planning and research in the earliest phases should be prioritized.