Re the Titanic, no, helms on large ships are not tillers. They turn to starb'd if you are trying to point the bow to starb'd.
But if the helm command had been preceded by "All astern flank", the helmsman might be thinking outside the box and taking the intended reverse motion of the ship into account. That's not normally what a helmsman does -- he puts the helm to starboard on a starboard command regardless of engines. But hey, it was an emergency and maybe he was rattled. Despite the engines, the vessel had forward way on, and would have responded accordingly if at all.