So even though Tom is exonerated of the assassination, he still shot his boss and killed the assassin in cold blood. How this does not even rate a suspension is insane. More insane is that Tom has a big attitude because Harry might have the new agent Adam run the operation. Adam is played by Rupert Penry Jones, who is a hundred times better actor than Matthew Macfadyen (Tom Quinn). It is not even remotely close.
As soon as I saw Penry-Jones I was hoping the end of Tom Quinn was near! Tom Quinn has the personality of a cry-baby. First it was all his pathetic drama with his girlfriends. Then it was him constantly violating the MI-5 rules. Then it was totally going off the rails, doing whatever he wanted, and shooting his boss. Also bullying his friends by forcing them to violate MI-5 rules as a show that they still trust him and are his friends. That is really vile for anyone to do.
Anyhow, in spite of all the stupid ways Tom has destroyed MI-5, Harry and the rest of the team are loyal to him. Tom doesn't get it, and continues to make everything about himself.