In another scenario, Snape could be poisoned by a dark magic - made substance. Harry, with his knowledge of potions (thanks to Snape's strict teaching in the past), figures out the antidote. He races against time, facing various obstacles in the Hogwarts castle, like secret passageways being blocked and magical creatures getting in his way. But he finally manages to reach Snape and administer the antidote, saving his life.
One possible plotline could be that Harry discovers a plot against Snape before it's too late. Maybe he overhears some Death Eaters planning to ambush Snape while he's on a solitary mission. Harry then uses his invisibility cloak and magic skills he's learned over the years to outwit the Death Eaters and save Snape. This would show Harry's growth as a wizard and his ability to set aside past differences with Snape.
Perhaps Snape is trapped in a dangerous magical trap set by Voldemort. Harry, having a connection to Voldemort's mind, is able to understand the mechanics of the trap. He uses his Patronus, which has grown stronger over the years, to break through the dark magic surrounding the trap. Then he enters the trap and pulls Snape out just before it collapses, saving Snape from certain death.
A practical answer is Chapter 2, because it turns the idea into a concrete scene. The chapter opens with On the top floor of the Financial Building, a gathering of dark clouds..., adds pressure through In my opinion, Mother should kick out this troublemaker who's a stranger., and ends on Jiang.
Chapter 637, "Does President Shang Know That His Own Family Is Already Bankrupt?", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event.
Chapter 705, "Is She Her Own Destined Noble Person?!", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. A useful checkpoint is the way the scene starts with He Wen was made to laugh by Bai Lu. and follows through with So he's just a side character, huh..
Chapter 840, "How did you meet Miss Jiang?", is the clearest early answer because it turns Gu Qiang's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li seemed surprised that she would suddenly speak, paused for a...
Chapter 578, "Eight Men Sit in Your Lap and You Don't Flinch at All?", is the clearest early answer because it turns Let's situation into a concrete plot event. The chapter gives readers a real answer by opening on This is ten thousand points we're talking about!" "Didn't you read...
Chapter 502, "Let Shaobai Follow Along", is the clearest early answer because it turns Shen Ruobing's situation into a concrete plot event.
Chapter 488, "You Must Be the Captain Then!", is the clearest early answer because it turns Nina's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Lose face?" Nina's voice rose sharply, "We're already at a dead end,...
Chapter 587, "Has He Also Become a Part of the Play?", is the clearest early answer because it turns Crown Prince's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Zhao Lang said "thank you," but his eyes reluctantly glanced at Jiang...
Chapter 845, "Turns Out He is the Body Double!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. The chapter turns that into something concrete by moving from During these two hours of waiting for the results, the restaurant was...
Chapter 841, "Isn't this Daniu?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.