It had stopped with its club half raised above his head and was looking right at him. Harry couldn't decide if that was good or not, but at least it meant Hermione was safe... for the moment.
Not wanting to be crushed by the creature or smacked by its club by getting too close, Harry flicked his wand at several broken pieces of toilet. The objects lifted into the air, hovering there, and another flick of his wand sent them sailing directly at the creature, pelting its face.
The beast roared and started swinging both its club and its free hand to try and swat the large chunks of toilet seat fragments out of the sky. Another flick of Harry's wrist sent even more broken objects flying at the creature, effectively distracting it.
"What are you doing just standing there!?" Harry asked, shouting at Hermione to be heard above the angry roaring. The girl looked at him like she had never seen him before, her mouth hanging open dumbly and her eyes wide. He wouldn't be surprised if she was going into shock. At least her trembling stopped. "Get over here!"
Hermione scrambled to her feet. The troll roared again and made to step toward her, but Harry sent another part of the rooms broken décor at it. The stall door smacked it in the face, causing it to bellow in both surprise and pain as it staggered back. In that time, Hermione ran over to him, and Harry did not waste another second in grabbing her hand and pulling her through the door in a dead sprint.
They had barely made it 10-feet from the bathroom when a loud roar sounded out. The sound was followed by the a loud crash as the troll smashed through the bathrooms entrance, sending stone fragments bouncing along the walls and floor.
It looked around, its head swiveling left and right before it spotted them running down the hall. Another loud bellow leapt from its gaping maw and it soon began charging them, its large feet smacking against the stone floor with the sound of war drum as it began to quickly catch up with its larger strides.
"Dammit!" Harry hissed as he let go of Hermione's hand and spun around. His wand was out quicker than the human eye could blink. He waved it at the suit of armor closest to the rampaging troll. The suit lifted off the ground and flew at the creature, smacking it flush in the face.
The troll angry bellow reverberated along the walls as its club swung down, hitting the chest plate. A loud noise issued from the plate mail, like the crack of thunder. The chest plate squealed as it dented and went flying into a wall where it dented some more, the wall itself cracking under the powerful blow.
Harry swore as the creature forgot about the armor entirely and turned its sights back on them. He looked left to see Hermione staring at the monstrosity in fear and swore some more.
"What the hell are you still doing here!?" he demanded. Hermione turned to him, her eyes wide and her face pale. "Get out of here! Go!"
"But—" Hermione tried to argue feebly, but Harry was having none of it.
"GO!"
In accordance with Harry's desires his magic flowed out, connecting to Hermione, compelling her to run. Normally, it would be very difficult to compel a magical being to do anything, especially subconsciously like Harry was doing, but with his desperation fueling his already powerful magic, the compulsion managed to take hold despite Hermione's resilience. The mousy-haired brunette's eyes widened as the desire to flee overcame her, and her body responded to the external stimulus by turning on the spot and bolting down the corridor.
His sigh of relief was short lived as the troll had closed in on him during his preoccupation. It swung its club down with a loud grunt, the heavy wooden object moving far faster than should be possible for something of its size.
Harry dodged by moving into a forward shoulder-roll that took him past the clubs point of impact. The club smacked the ground where he had been, denting it, sending cracks along the stone surface. Harry continued his roll, moving under the troll's legs.
He kipped back to his feet when he was behind it, his wand flashing out again, pointing at the creature's legs as he sent a leg-locking jinks. The spell struck the creature's left leg, only for nothing to happen. No straightening of limbs that had been locked in place. No loss of balance as the leg stiffened up. Nothing. It was as if the spell hadn't affected the troll at all.
Harry's eyes barely had time to widen as the troll spun around. It's club sailed towards him, the air screeching around it due to the speed with which it moved. Harry barely avoided the attack by letting himself fall backwards. He fell onto his back, then rolled with the move, before kipping back up to his feet and beginning to back pedal.
His wand arm flashed out, a slashing motion that he directed at the beast. A bright white light shot from the tip of his wand, the stinging hex hitting the troll in the belly, but again, there seemed to be little effect beyond the creature getting annoyed.
It roared at him, whether angered at not hitting him or the stinging hex, Harry didn't know. Whatever the case was, it came charging in once again and Harry was forced to sidestep another club swipe. He flicked his wand arm at another suit of armor and sent it at the creature, then another flick caused the suit to split into multiple pieces that floated around the beast in an effort to distract it, while he tried to figure out why none of his spells were working.
Could it be that he wasn't putting enough power into his spells? That skin of it's looked tough. Maybe if he just put more power into his spells...
While the troll was busy trying to swat the armor out of the air, Harry sent another stinging hex its way, this time with much more power than before. The spell soared through the air, a bright white light that smacked against the troll's hide.
The troll let out a roar of annoyance and Harry's eyes narrowed when he saw that the spell had not even left a mark. On a human, a stinging hex of that power would have left a welt the size of his head for several days without magical treatment.