Somewhere along the line, he had fallen in love with his little sister's best friend. He had known her for years, twenty to be precise, and yet it took him almost fifteen to realize she was more than just a curly little thing with a cracking voice whenever questioned. So watching her showing off her newly acquired engagement ring on her small finger was a rather painful situation to deal with.
Had he acted sooner, he might've had a chance with Gwen: but Lance, charming Lance, handsome Lance, the same Lance he had hated since elementary school for picking up on his little step-brother, had knocked her off her feet and now asked to be his forevermore. Arthur Pendragon wasn't one sensitive bloke and, most of all, wasn't one of those boys who show their feeling easily. So seeing both his sister and brother staring painfully at him was getting rather frustrating; he had to get out of that place but there was a tiny little problem: that was his place, too.
He could have easily come up with an excuse and asked his brother to pack everyone up at the end of the party and close the house. Or he could just say that there was a case that needed to be finished before the morning, but nobody would've believed him: unfortunately he never left the office without being sure that every file was perfectly closed.
-There- Gwaine, Gwen's older brother, passed him some keys-These are for my place. Just go there, nobody will come search for you-
-What are you talking about?-Arthur questioned with a panicked look.
-Mate, just go. Marlin made up an excuse for you: that would be easier than explaining Lance's murder, don't you think?-
Arthur frowned and got the keys into his pocket. He turned to see his sister talking to the lovely newly-engaged and Marlin simply looked at him and gestured to go, mentally adding he was going to call him later.
He left the house and headed to his parked car, starting the engine with fury: why was he so damned slow? He was taught since childhood that a great lawyer never lets his feelings visible, but sometimes that just complicated his life so much. Arthur believed his father to be the smartest man on Earth, but his early life lessons really had an horrible impact on him.
Gwaine lived in Belgravia, having inherited a rather large flat from his maternal grandfather after his passing; that was indeed the perfect place to cool off and think lucidly about things. Gwen was his friend , after all, and if that disgusting Lance made her happy, then he would have to shut up and help out during the wedding preparations. And maybe create some trouble to the happy couple.