There’s a theory that Mrs. Hudson’s husband was both verbally and physically abusive, which is why Sherlock guaranteed him being locked up. Which is why Mrs. Hudson flinches so bad when Sherlock slams his hands on the table. Which is why in this scene Sherlock is going to tear Mycroft’s head off. Which is why, when Mrs. Hudson gets beat up by the burglar, Sherlock goes all ape shit on him and throws him out the window. Because he adores Mrs. Hudson and nobody gets to treat her like that anymore.