This steward handed out lifebelts to steerage passengers offscreen. He went then up to the deck with a few remaining lifejackets.
On his way there, he encountered a panicking passenger (Rose). Doing what he was ordered to, he told her not to panic, put her lifebelt on and go to the Boat Deck. Rose, however, tried to pull him the other way to her boyfriend in distress. Steward 4 constantly interrupted her attempts to explain her situation.
Finally, Rose shouted "Listen!" and punched Steward 4 in the face. Shocked, he dropped his lifebelts and simply said "to hell with you" before bailing away.
He must have arrived on deck before most of the lifeboats were gone, so it's likely he boarded one.