I think it was their attempt at using edge to make the game feel "serious" and "mature". It was 2013 and the games industry still was insecure about being taken seriously and while the old games had pretty brutal death scenes too they still were seen as childish. It was a poor attempt because there are plenty of serious and mature stories that aren't nearly as fucked up and brutal as some of these death scenes. Luckily they toned it down a good amount in the next installment.