Series 9 Episode 2 discussion

[Annie]

I don't think Vaughn had a stroke, I think that's just what he's been telling people. My theory is that he took a bullet to the head, and that it was possibly John who shot him as well. Either that, or John/Lucas and Vaughn were working on something really dangerous that caused Vaughn to have a stroke just from being around it. In Spooks that is probably not impossible...