Magius strode out of the front doors, eyes aglow with magic, worried. He had seen Snape's message and even believed with the spirit the man had shown they would win through, but he had expected them in sooner than now. With that in his mind, he strode into the night, white robes billowing as cold assailed him. He was a war wizard, a White Robed Wizard of High Sorcery, and a war-proven man, but right now, more than anything else, he was a man worried about a friend. Severus Snape had proven himself as one of the few friends he had ever found in life, either here or home, and he would not let one down, ever.
His steps quickened...
Above, seeing the darkness spread, and seeing the lights go uttewrly black in the hotel, Harry knew the time to act was come, and perhaps almost gone. he cursed himself for not acting before, and moved to the edge of the roof, eyes determined.
Summoning the memories of Lily's birth, of her bravely going out into the night, and of knowing her love, he raise his waned, and then snapped it down at the hotel. With all of his will, he cast a spell.
"LUMOS MAXIMUS!" The spell departed him and hit the hotel, and he sagged backward as a wave of light rolled down the walls of the hotel, turning the whole building, for at least a short time, into one bright lightbulb, lightbulb, like those the Muggles used for games. He grinned as he turned, and made for the elevator.
The light caught Magius by surprise, and he swore, and thanked Paladine that he had been turned away from the hotel as it lit up, gleaming in the darkness. And in that light, he saw the party moving toward the hotel, and the Dementors near behind them.
Stopping still, he raised his wand, and summoned the magic, then shouted the spell. "Expecto Patronum!" He concentrated, filling it with his magic, summoning every ounce he could. And from Snape's patronus, a second split, a giant shield flaring into place, then doubling in size, square between the party and the Dementors. He concentrated, holding it, and retreating it as the party did.