I think B is smart in doing so.

B obviously is not in the inner circle of big boss. so he tries his best to make the situation work for him, by being collaborative. Nobody is irrelacable. So his group would be fine even if he lost one good person. He can make it up by using the others more effectively. And C would be happy. A would think B is a team player. Thsi si teh best scenario. The "廢人" can be used as a very good under-the-table communicator with big boss. People like that are very usefil in a group for public relation. He can be productive in a different way. Everyone is an asset. The question is how to use each individual. B is "Lao Mou Shen Suan"