sob... just erased my post. I watched the replay. I had 2 uber derp moments. The first was me fucking up followed by the team just completely derping. I'll prob make a video to showcase it in all its glory. So, I get caught in the jungle by karl with his whole team in tow. Completely my bad for positioning. My team is in the area, but no where close (except jona). I almost instantly die after laying down a very small amt of dmg. Jona then decides to engage a 5v1. He manages to kill 1, but hands out 4 assists and a kill. Then, the ultimate derpy moment. Wukong and naut decide they will ambush their near full hp team. Our taric had enough sense to not be there for the ambush (he shouldn't have been there... twas a bad idea). Anyway, that results in 2 more deaths for us and none for them. Then they take baron. Prior to this moment, we were up like 27 to 10 or something silly.
My other uber derp moment was the one dax mentioned. Broken charges in after jace and I follow. We kill jace. I've completely ignored the 4v3 team battle happening below. My team gets slaughtered and we take our 1 kill and get like 4-5 deaths. Brilliant pacov.
The other moments, the one that actually cost us the game, happened in between my 2 derps. At 26 min in, its 33 to 17. We are making a strong push on their base and get an inhib. At this point broken decides to wander off... while we are all standing in the middle of the enemy teams base. He then decides to back door, but the creeps are almost all the way to our bottom tower... he then proceeds to push the lane until he, after a few min, makes it to the tower. Then he does a small amount of damage to the tower and is promptly killed giving 1 death + 2 assists. While he was doing this backdoor, our team was forced to engage. Wukongs ult was up the whole time. We were up by 12k in gold and leading by 16 kills. In short, if that engage went well, the game would have likely ended. His ult would likely have made a huge difference on the engage or at enabled us to break off.
Another derp moment happened later when our naut choose to wander off to solo top while the rest of the team pushed bot. Again, due to all the cc, we are caught in a full engage without a ton of cc or chance to peel. This resulted in 5 deaths on our team as naut then came in after we were dead to pick off the incredibly valuable 1/10/3 ash. That also resulted in a free baron.
Anyway, we really just needed to take our huge lead and put it away early. Not staying together when it counted easily cost us the game imo.