Sure, this may be an abrupt shift in tone, and it may be drawn like an eroguro, but i don't think it's necessarily bad, it's probably the best chapter yet. Eroguro is supposed to be equal parts arousing and disgusting, so that whoever is aroused by blood and mutilation may rethink their choices a little, and this is reinforced by the sick stories that commonly have some social critique, at least more emphasized than they would be in an incest ntr doujinshi. I think this is doing that too.
Read Geiger Counter. It's unironically a masterpiece.