Remus saw the Trio disappear in the entrance to the Whomping Willow and decided to follow them, dodging stray curses and hexes as they headed for unknown targets. He stayed behind after the Trio left, hidden in the shadows of the passageway, and slowly made his way up to the Shack to see what had transpired. Upon seeing Severus, he immediately rushed to his side and did his best to staunch the flow of blood. He grabbed a chocolate bar from his pocket – it's a magical elixir as far as Remus is concerned, and so he always carries one – and offers bite sized pieces to Severus. Remus knows it won't do anything for the poison in Severus' system, but the chocolate restores magical power. Remus correctly assumes that Severus – a preeminent Potions Master – will be carrying anti-venom and blood replenishing potions on his person, and so once Severus has regained enough strength from consuming the chocolate, he directs Remus to the hidden pocket of his robe, muttering something about 'being expeditious' and 'not spilling a drop, you infernal wolf'. The combination of these factors allows Severus to stand with Remus' help, and together they make their way into the castle from another passageway and seek out Madam Pomfrey.
... to which snow awarded 4 points ("I find this a totally acceptable idea of how Remus saved Severus with chocolate.")
And then I added:
Of course the diary doesn't make sense. Only Dumbledore and the Trio knew the Horcruxes were real. Even Lucius, who recognized the diary as a Dark, magical object, was unaware of its true purpose and consequences. Slughorn knew what Horcruxes were in theory, but didn't know they were hunting them for real; Regulus discovered the secret, but thought the locket was the end-all-be-all of it; Kreacher didn't give a rat's ass because elves don't bother themselves with wizarding squabbles. Besides, even if someone had told Remus about the diary, it was, at that point, an inert Horcrux. Exactly what could it have done for Severus aside from trapping his soul?
... to which snow awarded 5 points ("You know, this was a such a well thought out, logical response that I will give you another five points just for pointing out how incredibly flawed Roo's logic is.")