Magneto took his chance and left the scene and his struggling son. Although his destination was ultimately the X-Mansion, he had a stop to make first. There was no doubt in his mind that Pietro would warn the X-Men and so, without a little leverage, he knew that this might all be for naught. Cathartic as wrecking the mansion would be, it would do Magnus no good if he didn't get what he'd come here for.
Sure that his son would not expect this, he did not race back to Pietro's apartment. He took his time, formulated a plan as he walked the few blocks back. A trade would work well, though he decided Pietro's failure could not go unpunished. He'd think of something fitting. In his son's building he took the elevator up next to an elderly woman with a tote bag of groceries who tried to make small talk with him as he ignored her. She got off, grumbling, a floor below the one he needed. The hallway was empty and the light fixtures swung as he walked under them, drawn by his power and turning towards the door as if to see what would happen next. The lock was easy, it turned with a solid click, and he rattled the handle and waited a long moment, taking perverse pleasure in letting Wicked believe this was just her husband returning home.
Readying his shield of electro-magnetic energy, Magnus sent his powers to feel out the apartment, and then he yanked the door from its hinges. "Hello, Wicked, your father-in-law's come for a visit," he said as he stepped inside, wriggled his fingers, and ripped the television from its wall mount to send it hurtling towards Wicked's head. "I never did send you a house warming present," Magnus remarked as the metal appliances slid across the room and crashed into walls and through windows. This was good. This was definitely cathartic.