The iPad battery died and it completely set him off. Despite Brittany's efforts to make him happy with an alternative while the iPad charged a bit, Jacob was already swinging and biting and pinching her as an outlet for his frustration. The iPad got thrown several times, at one point she had to lock herself in my bathroom while Jacob threw objects at the door from the other side. She has been trained in self-defense and restraint (the same program we are currently learning) yet was unable to use her skills to contain him and block his limbs. In desperation, Brittany screamed at the top of her lungs and Jacob stopped his freaking out and stared at her for a moment, and then walked away. End of tantrum.
And I was leisurely wandering around a garage sale a few blocks away, completely missing a phone call from Brittany. I came home about 30 minutes after the tantrum had ended. Jacob seemed like nothing had even happened, but Brittany was obviously in recovery mode. Tears were shed. She told me the iPad was broken (it isn't) and apologized for making him mad and told me the neighbors may be curious about the scream. I tried to reassure her was not an isolated case and his reaction had nothing to do with her respite skills. It could have been any of us in her shoes. I really, really hope this isn't the end of another caregiver.