Miscommunication can happen easily and quickly. Once something is misconstrued, tensions can flare and conclusions jumped to. Once the situation has escalated, it becomes very difficult to come back and dissect what's really going on.
When you see the situation getting out of control, try your best to put on the brakes. Halt the conversation, take a second to breathe, and have parties explain their sides with a level-headed attitude. Progress is rarely made by yelling.