Even though Roc was placing a strong angry front towards the Cloud tribe and Wolf, he knew the dangers of their situation.
Roc was no fool controlled by his emotions. The only reason he came without any help from Light was to resolve the situation as soon as possible.
Roc knew that if he had gone back to the tribe to gather men then things would escalate out of control. Their tribe couldn't afford to lose people in fighting as winter was approaching and they already lacked men.
Roc had believed that as he already knew Wolf through his sister Daisy so it would be easier to talk with him and maybe even resolve the situation quickly.
Realistically speaking, even if the four of them shoot arrows at the same time, they could only shoot four people. In case someone missed that it would be even lower. Killing three or four people would have no effect on the other nearly 30 people who still had stone spears in their hands and could simply rush them down.
