Draco noticed almost immediately that something was wrong, because Henry did not do what Draco had expected.
He did not turn and begin hunting the Golden Snitch. He did not try to press the advantage.
He hovered in mid-air, his brow furrowed slightly, watching Harry.
So Quirrell had made his move.
Henry observed Harry being thrown through another violent sequence, his hair whipping across his face, his knuckles bloodless.
He already knew, broadly, what was coming next, Hermione would shortly produce her small blue flame and manufacture an incident involving Professor Snape's robes, breaking his concentration, and Harry's broom would return to normal.
But that raised an interesting question.
What if Harry were pulled to safety before the broom stopped its rampage on its own?
The outcomes were straightforward: Harry would be off his Nimbus 2000 for the rest of the match, leaving Gryffindor's Seeker without their finest instrument; and the image of a Slytherin Seeker abandoning his pursuit of the Snitch to save his direct opponent, in front of the entire school, would be difficult for anyone to forget or misread.
The risk was negligible. The return was considerable.
As for whether this might attract Voldemort's attention, that was not a serious concern.
This was clearly Quirrell acting on his own initiative. Voldemort's primary objective was the Philosopher's Stone, and creating a public spectacle like this before obtaining it would be entirely contrary to his interests.
If anything, being saved would be an inconvenience to him.
It was an easy decision.
In the fraction of a second before Harry was swept downward again toward what would have been a heavy impact with the pitch, Henry acted.
He pressed the broom handle down sharply and the Nimbus 2000 responded with a low, rising whistle as it tilted into a near-vertical dive.
The wind tore at him, flattening his dark green robes against his body.
"What is Wales doing? Why isn't he going after the Snitch?" a Slytherin student in the stands called out.
"He's going after Potter!" someone nearby shouted.
At the last possible moment, Henry pulled level with Harry a few feet above the grass and raised his wand, directing it beneath him.
"Wingardium Leviosa!"
An invisible cushioning force caught Harry mid-fall, decelerating his descent sharply without stopping it entirely.
The broom still dragged at him erratically, pulling him sideways in short, lurching movements a few feet above the ground.
Henry did not stop. He manoeuvred alongside Harry's thrashing Nimbus 2000, keeping pace at low altitude, his wand moving quickly.
"Reparo!"
The curse holding the broom was beyond a first-year's straightforward countercurse, that much was immediately clear.
But Henry's assessment was rapid and practical: since he could not stop the broom directly, the priority was separating Harry from it.
"Harry! Let go of the broom! Trust me!" He pitched his voice above the wind, keeping it steady and entirely certain.
Harry was dizzy, his arms burning with the effort of holding on, his grip beginning to fail regardless of his will.
He heard Henry's voice through the noise and the panic, and the quality of it, the total absence of alarm in it, cut through to something underneath his fear.
He looked sideways at Henry, who was right there beside him, and saw nothing uncertain in his expression at all.
At the top of one last upward lurch, where his speed fell away for a moment, Harry shut his eyes and released the broom handle.
Henry's Levitation Charm met him instantly, precise and steady, and Harry descended in a slow drift, like something that had forgotten it was supposed to fall quickly.
The Nimbus 2000, suddenly riderless, made one final frantic series of gyrations and then struck the distant wall with a hollow thud, sliding to the grass.
Henry lowered his altitude and brought his broom alongside Harry as he reached the ground.
Harry was ashen, breathing hard, his arms shaking visibly, but he was unhurt.
A deep, complete silence fell over the pitch.
Every person in the stands was staring at the same thing: a Slytherin Seeker, at the most critical and contested moment of a match, who had not gone for the Snitch, had not pressed his advantage, but had used his magic to pull his direct opponent, a Gryffindor, out of a fall. And had done so with the calm economy of movement that belonged to someone who had already decided before he moved.
Madam Hooch was the first to act. She blew the whistle to suspend play and flew over.
"Potter. Are you hurt? Should I take you to Madam Pomfrey?"
She looked Harry over carefully, then turned to Henry. "Mr. Wales. You were precisely in time."
In the Gryffindor stands, Ron let out a long, shaking breath and looked at Henry with an expression that mixed relief and disbelief in roughly equal measure.
Hagrid's voice boomed from the far end of the staff table, warm and unambiguous: "Well done, Henry!"
The Slytherin stands had gone very quiet. Draco's mouth was open. Pansy and Daphne exchanged a glance that communicated several things at once without settling on any of them.
"How are you?" Henry said to Harry. "Can you continue?"
Harry looked at his Nimbus 2000 lying crumpled against the wall.
Something moved across his face, frustration, or the specific anguish of a rider for a ruined broom, but his expression settled. He could not trust it again today.
He shook his head. "The broom is done. And I—" His arm trembled as he started the sentence.
A figure came running from the direction of the castle at speed. It was Professor McGonagall, her face set and pale, a Seven-Star Sweep under one arm.
"Potter!" Her voice left no room for argument. "Take this. The match continues."
Harry drew a slow breath, took the broom, and swung onto it. His face was still white, but the stubbornness had returned to his eyes.
"I'm all right." He looked at Henry. "Thank you. For pulling me off."
Madam Hooch assessed both Seekers. Harry pale but upright, Henry composed—and blew her whistle.
"Play resumes!"
Both teams rose into the air again.
The Seven-Star Sweep handled nothing like a Nimbus 2000, and Harry's face showed the effort of adjusting to it as they climbed.
Then, barely ten seconds after play resumed, Henry caught a flash of gold at the edge of his vision.
It was on the western side of the pitch, perhaps ten feet below the Slytherin goalposts, hovering low over the grass, its wings moving so fast they were invisible, the sound of them swallowed entirely by the wind and the crowd.
At almost exactly the same moment, Harry saw it too.
He spun his borrowed broom in a sharp arc, flattened himself against the handle, and drove westward at everything the Seven-Star Sweep had.
Henry's Nimbus 2000 responded in the same instant, faster, more immediate, snapping into acceleration without the fractional lag of the older broom, and pulled level with Harry in moments, drawing half a length ahead.
The roar from the stands came up like a wall of sound.
"Both Seekers have spotted the Snitch at the same time! They're both in the dive! Wales is half a length ahead, but Potter isn't giving an inch! They're going to collide, Merlin, they're going to collide!"