Bad ending, sweetness
One thing that you didn't do was take what was HIS. Charles Xavier, no matter how much the man was on the wrong side of things, was his and his alone. If anyone were to hurt the telepath it would be him. Not some humans who thought they could take the man from him. That just didn't do. So when he finds that Charles isn't where he should be back at the mansion he has Emma seek him out. It's the grave look on her face that has his anger spiking.
Erik made them take him to the compound and he couldn't help but smirk slightly. Oh how stupid they were. Stupid enough to have metal in places he could rip apart. So if Charles was paying attention to the sounds (the scientists and guards sure were) there's the creek of metal and the sounds of screaming throughout the building. He will kill anyone and everyone to take back what's his.