"I let them in my head," Sirius argued, and his voice was lower now, more rough. Because he should have been better -- he had been so convinced when he was sixteen that he wouldn't let anyone separate him from them, and there was no reason that he should have given in. He knew Bellatrix. He knew the wicked games she was willing to play, the depth of the darkness that filled her. He knew that she would want to get back at him. And so why had he ever believed them?
He didn't even notice the use of Pads, or the subsequent apology that it drew from James. He was too intent on his own whirlwind of emotions