Throughout the during the duration of Blake successfully arguing all points and claims Matthew had tried to make Matthew actually looked hurt as if it was someone who was attacking him without unprovoked and not someone standing up for their friends. It was probably due to it being Blake who was doing it, since she was the only one he had wanted to become friends out of the group. Which Blake didn't fail to mention either, making sure to keep details about his shitty reasons for it.
When Blake was done Matthew waited a moment with speaking, placing the phone with the picture that had helped in proving him wrong down, trying to come up with something to say to defend himself further but just as he was about to open his mouth he was interrupted.
"Matthew, seriously, don't," Gabi said, sternly, clearly not wanting to hear more of his bullshit and not wanting him to fuck things up further, "You're wrong."
And Matthew didn't say anything else, because he usually listened to Gabi and now was apparently not an exception. He did, however, stare at her in utter disbelief as if she had completely betrayed him. And then he looked out over the rest of the people, being met with angry faces from Bella, Elliot and Blake, a Matilda who looked seriously upset and a hurt Samuel. Then he just stood up without another word and left the house, door banging loudly behind him.
"I'm going to make sure he doesn't do anything stupid," Gabi said as she stood a short moment of silence later. It was probably a good idea. Other than Samuel she was his only friend in the room and Samuel was obviously not in the right frame of mind to follow anyone and make sure anyone was okay, especially not Matthew. He felt terrible because of what Matthew had said, he felt guilty because Matthew was his friend, and he was feeling seriously uncomfortable and on edge from being in a room with so many angry people, even if no one had technically been yelling.
What ended up breaking the silence Matthew and Gabi had left behind when leaving was Samuel letting out a quiet sniffle as tears started running down his cheeks. He stood up as soon realised he was crying, he couldn't deal with anyone seeing him cry, except for Roman, who's hand he grabbed to pull him up with him. He needed his boyfriend even though that was the exact kind of thing Matthew had just told them made him too dependent on him.
He didn't let go of Roman until they were down in their room in the basement, there he just sat down on the bed, arms wrapped around himself, and turned down and continued to let the tears pour out his eyes.