Complex sentence: Lightoller stayed until the last, was sucked against a grate and held until he was under water, but then was blown from the grate from a rush of warm air as a boiler exploded and clung to a capsized collapsible boat with 30 others until their rescue.
Split into simpler sentences: Lightoller stayed until the last, was sucked against a grate and held until he was under water, but then was blown from the grate from a rush of warm air as a boiler exploded. He clung to a capsized collapsible boat with 30 others until their rescue.