Severus had drawn the late patrol at eleven o'clock for the first night and last night. Both nights he had found Quirrell lurking about the third floor corridor. When questioned, Quirrell stammered that he was making sure nobody was trying to break into the room, but something about his demeanor sent up red flags for Severus.
The next morning before Harry's first flying class; Severus shrank his Nimbus, put it in his pocket and waited on a parapet overlooking the grounds where the flying lessons were held. It was too close to the Whomping Willow for his comfort and he just had an uneasy feeling. He remembered how Lily used to tease him about 'his uneasy feelings' and call it his radar. He had lived many years with an alcoholic father who had a hair-trigger temper so that may be when his 'radar' developed, but he also always listened when it was warning him about something.
He watched as the Ravenclaw's and the Hufflepuff's and lined up facing one another. He spotted Madam Hooch coming and watched as she strode between the students wishing them a good morning as she passed. She turned and stood at the head of the two lines with her hands on her hips and said, "Good morning, Class."
"Good morning, Madam Hooch," they answered. The brooms were laid out in two neat rows across from one another
"Well, what are you waiting for? Choose a broom! Come along, hurry up! Put your right hand over your broom and say up."
They did as she told them. Severus noticed Harry's broom jumped into his hand straight away. She gave them their instructions. "Now, when I blow my whistle, you kick off from the ground hard. Keep your broom steady, rise a few feet, and then come straight back down by leaning forward slightly. On my whistle – three – two –"** Madam Hooch blew her whistle. Harry did as she instructed, but instead of rising just a few feet, his broom shot up into the air ten feet and took off, heading for the Whomping Willow. "Mr. Potter-Snape, come back here!" Madam Hooch shouted, jumping on her broom to go after him, but it threw her off.
Severus resized his Nimbus and kicked off, going after Harry's broom. He leaned forward slightly to increase his speed.
Madam Hooch understood without being told that something was wrong with the brooms and ordered all the children to drop them and move completely away from them.
Harry was pale and holding onto his broom for dear life. He couldn't seem to do anything with it, turn it around or slow it down. It was like it had a mind of its own. He could hear his year mates and classmates yelling and screaming below. He suddenly saw his dad on his Nimbus flying beside him. "Dad! I can't get it to stop or slow down and I'm heading right for that huge tree!"
"Harry, do exactly as I say, all right? Lean sideways towards me," Severus ordered. He flew as close to Harry's broom as he could, steadying his broom with one had while he reached out for him. Harry used his father's arm as leverage and was able to pull himself over onto Severus' broom. Severus put his arm around Harry, turned his broom around in a wide circle heading away from the Whomping Willow. Harry's broom went flying into the tree and was smashed by it into a million pieces.
Severus was heading down to land when he caught sight of the purple turban. What in the hell was Quirrell doing here when he was supposed to be in class? Severus pulled out his wand and yelled, "Stupefy!" Quirrell slumped to the ground. If he was wrong he would apologize, but it was better to be safe than sorry especially after catching Quirrell in the third floor corridor two nights in a row. He knew that the headmaster, Filius, whose responsibility it was to place the safety charms on the school brooms, and the Defense professor were the only ones who were able to take the safety charms off the brooms. Even Madam Hooch couldn't. If someone were intending to kill Harry they would need to take the safety charms off all of the brooms because they wouldn't know which broom he might choose.
He landed, helped Harry off of his broom and made sure he was all right before sending a Patronus to Dumbledore and another to Madam Pomfrey. "Wait here," he said and ran over to Quirrell. Just as he approached him he saw something that could only be described as a black mist rise up out of Quirrell's unconscious body and flee.
Madam Pomfrey followed by Dumbledore came running out and stopped suddenly when they saw Severus bent over Quirrell. "What happened, Severus?" Dumbledore demanded.
"I'll explain inside. Professor Quirrell needs to taken to the Infirmary," Severus said to Madam Pomfrey. "Professor Flitwick will need to recast the safety charms on all the school brooms. Somebody has taken them off." He held out his arm to Harry who ran over to him. "Go on to your next class and I will see you at lunch."
Harry gave him a tight hug. "Thanks for saving me, Dad."
"That's what fathers are for, Harry," Severus replied. He watched as Harry and his year mates and his friends went back inside the castle.
Madam Hooch strode over and began berating Dumbledore. "Headmaster, I've told you for years that the school brooms need to be locked up securely and now look what has happened! If all the children had kicked off at the same time as Harry, we'd probably have dead children because neither I nor Severus would have been able to save all of them!"
Dumbledore held up his hands. "Please come to my office after lunch, Madam Hooch and we'll discuss the incident then."