Premise: Quirrell plays the game one level higher than Harry Potter.

Observation: This entire incident is uncharacteristically sloppy. Why were the unicorn corpses found? Why was Quirrell discovered?

Observation: Harry Potter is now really pissed off that herds of unicorns to slay aren't standard procedure for stable-izing people with life threatening injuries. He has just been given another "if only" to fixate on. It has been brought to his attention in ways that wouldn't trip his "why am I being told this" sense.

Father had told Draco that to fathom a strange plot, one technique was to look at what ended up happening, assume it was the intended result, and ask who benefited.

Hypothesis: Reminding Harry that there were ways the wizarding world could have saved Hermione was the primary effect. Possible secondary effects may include impressing on Harry just how ridiculously powerful he is. Perhaps implanting the desire to save Quirrell into Harry's mind? Quirrell may not actually need the blood right now, though I suspect it doesn't hurt.