What is the difference between "passage" and "safe passage" used in rule 8,9,10 and 18?

Not to impede Passage means not to come to a situation where risk of collosions arises and never to imepde passage; its like always the give away vessel. Fishing vessels are not supposed to fish in the traffic lanes and if they do they are always give away vessel

While for safe paaasage;  eg vessel less then 20 mtrs in the TSS  when coming from inshore traffic zone and situation comes where she is a stand on vessel in a crossing siutation with other power driven vessel like loaded VLCC and if it takes action that will land him in danger then sailing vessel should give safe passage to tanker or not to impede safe passage.

Hope I am correct.