Heh, definitely a good, action-filled start that catches the reader's interest and attention. It should be interesting to watch the two of them work through the potions and then get together to deal with the situation. Given that he seems to have a genius for "muddling through" and that she's rather learned and powerful, it should be interesting, to say the least.
Author's response
That's pretty much how I see Hermione. She sees a problem, projects several possible solutions, selects the optimal response and acts upon it.
Harry says, "Hey there's a problem.