Kiddo, a keeper normally makes such moves in dying minutes. He came out in 89th min, IIRC. I hope this is the first time you've seen a keeper make such move 8-10 mins prior to final whistle because I've never seen it in my entire life. The timeframe )8-10 mins) is quite significant in these stages of a cup competition. Teams like United have won the Champions league by scoring 2 goals in 2 mins of stoppages. Dortmund eliminated Malaga by doing the same last season. His decision is equivalent to a keeper getting into his opponent's box in 84th minute of WC final, in the event his team's trailing by a goal. Keepers normally make such moves in the last 2-3 mins. In any case, it didn't really matter but like I aforementioned, I'd have been outraged if we'd conceded a goal 8 mins due to his decision, 8 mins prior to final whistle being blown. 

Also, shit happens but the goal was 100 percent his fault. It was a massive cockup on his part. The cross had no significant pace or power. He should've easily grabbed it or just punched it. I'm willing to give him the benefit due to the ground conditions as the ball slipped through his hands. But that was his mistake. Simple as that.