The JHU Samurai seems like a pretty clear cut case to me
Proportional force and legal requirements to respond with proportional force are sensible, but I think it's pretty clear that this student was engaged in self defense and not maliciousness with an excuse.
The student says that the burglar lunged at him, and he defended himself with the sword in no more than 2 cuts, according to police. He severed the burglar's hand, and then cut open his chest. The burglar died from the injuries, but the student called emergency services and cooperated fully with police.
It seems most likely to me that he acted to defend himself until he was no longer in danger, then immediately sought emergency service intervention like a socially responsible person.
He was released yesterday afternoon. I do not think the Maryland AG should press charges.