The initial primary explosion could cause significant enough destruction to the ship that it acts like the “scatter charge” in a thermobaric weapon, spreading the undetonated oil sufficiently into the air that a larger percentage of the onboard oil is detonated as part of a “single event”…
However the more likely and no less disastrous outcome is the primary explosion of the fuel vapour damages the ship without sinking it (the explosion will be centred on the upper portion of the storage tanks) most likely blowing the top off of one (or more) of the storage tanks and potentially damaging the structural integrity of the ship without sinking it. An extremely likely outcome from this will be ignition of whatever remains of the oil in a burst storage tank, (which even if not “burst open” will likely have been structurally damaged so that fresh air can get in) leading to a fire onboard and due to the established lack of maintenance, that fire has a high likelihood of spreading through much of the ship (possibly aided by any oil movement induced by the primary explosion) which will heat up any undamaged storage vessels and turn them into (depending on the state of the pressure relief valve maintenance) potential pressure cookers full of fuel or sources of further burning fuel vapour…
So I don’t think they were trying to necessarily mislead as much as simplify the scenario for the audience. Most people don’t find it interesting to dissect cascading failures and map out the energetic potential effects. Most people would be fine saying “it blew up” even if it was technically two or three individual explosions interspersed between hours of being on fire before one final still in tact hot tank of oil went off like a pressure cooker turning into a fuel air explosion that shredded the ship into shrapnel.