It's a grim reminder of the kinds of things they've had to deal with. The fact Mycroft tased Sherlock is definitely a surprise though.

While somewhat pained imagining them going through this, it's long enough ago that Ted can keep it together.

Though when she says they shot that man in front of her, something in Ted tightens, and so does his hand on hers. It's like he can hear the shot in his head, and he clenches his jaw a bit.