Turnbull was 5' 9" (1.75 m) tall, white male. He had short black hair and brown eyes. During his appearances on the show, he wore a standard white 3rd class steward's tunic.
When the ship is sinking, Turnbull is holding down Third Class passengers with Hart and two other stewards.  Hart wants to rescue the women and children, but Turnbull keeps them all down. Hart brings a group of women and children up, but Turnbull quickly cuts off the line. Jim Maloney argues with him, but the arrogant Turnbull pushes him back down. When Peter Lubov interferes too, he grabs Turnbull and allows Maloney's family to escape. An unnamed steward frees Turnbull and closes the gate. Turnbull grabs his keys and locks the gate. 
Some time after, Sixth Officer Moody arrives at the scene, joined by two seamen. Turnbull tells Moody that the Italians are safely under lock and key. Moody warns him he must not forget to let them out.
When fireman Mario Sandrini appears on the other side of the closed gate and causes an uproar among the trapped passengers, Turnbull opens the gate and drags him in. All Third Class passengers escape, and Turnbull desperately tries to close it again, but he is pushed to the side and gives up. Meanwhile Sandrini is locked up with the Italians.
Turnbull leaves steerage and tries to get to the deck. Steward Sandrini stops him to ask where the Italians are locked up, but Turnbull brutally says "Why, are you anxious to join them?" Eventually, he reveals where they are. When Sandrini goes to rescue them, Turnbull shouts at him "You won't get them out! The door is locked! And it'll stay locked, until it hits the ocean bed!!!"
Turnbull leaves the flooding corridor and heads for the boat deck. 
He is never seen again, he died in the sinking because he was still on board when all lifeboats and all but one collapsibles were gone, and he also wasn't on the last collapsible.
Deleted scenesEditThe following trailer for the miniseries includes a few shots which were deleted from the final episodes. One of them shows Lubov slowly strangling Turnbull while the Maloney family escapes, and another shot shows Turnbull desperately trying to catch the passengers as they escape through the open gate.
Turnbull is portrayed as a racist bastard, seemingly executing orders from his chiefs but:
First, he refuses to let Steward Hart take the women and children to the lifeboats, saying they got their orders. Now he appears to be a 'good man' just executing the orders he got.
Next, he knows some seamen have put the Italians under lock and key after getting orders from Moody and Bruce Ismay to keep them under control.
And when Moody tells him "don't not forget to let them out", he simply ignores this order and walks by the cupboard they are locked in, only trying to save himself. He is revealed to ultimately do only what he wants and using the orders to justify his actions.