英语提问：求各位大哥哥姐姐们帮分析以下英语句子结构。
It had moved off very quickly,and while the men were swimming towards the shore,the boat moved in a circle,came straight towards them and only just missed them.这句话中我主要不理解while the men were ...towards them这段，不是说简单句里面不能同时出现两个谓语动词吗，这里在没有相关连接词的情况下却出现了moved和came两个谓语动词，这是这么回事？
