What could swimmers have done when caught in Stanwell Park's ocean drama last week?"Not much," according to rip expert Rob Brander."In that situation, it was really about just keeping your head above water."Dr Brander said there was also little lifeguards and rescuers could have done in the face of an event where conditions conspired to bring about life-threatening circumstances.The University of NSW lecturer was quoted in the Mercury last week saying that the best chance a swimmer had was to swim between the flags and, when in trouble, float, stay calm and signal for help.But Friday's tragedy was an exception to the rule.A strong groundswell, remnants of a cyclone, large sets of waves and a low tide - all regular occurrences on their own - combined to produce a rare "flash rip".The three council lifeguards, already aware that the conditions were changing, moved into action.But they were overwhelmed as one person after another was swept into rip channels on either side of the sandbank, some reportedly carried as far as 200m out to sea.Dr Brander said while the most common rip was not characterised by breaking waves, flash rips involved breakers that could swamp a swimmer."Flash rips are different, they don't sit in channels, they just pop up and disappear and it's really hard to spot them. They don't last very long and it's impossible to predict them," he said."I think what happened is a lot of people took in water because at the same time the rip was flashing out, there was still waves coming in and they were getting hit."Dr Brander said it appeared Friday's tragedy was "just a bad combination of everything conspired".He said the best chance for survival would have been to work with the waves until help arrived."When your head's above water, try and take big breaths; go under the waves and pop up after they pass," he said.Surf Life Saving Illawarra vice-president Ken Holloway said Stanwell Park Beach was graded as a dangerous beach, safest for semi-experienced swimmers: "It's an open beach, where it's open to all the swell directions whether a southerly swell or an easterly swell or north swell. If there's a wave around, Stanwell Park will get the wave."