in oredr not to be disturbed,i spent three days ()up in my s

locked是过去分词短语作主语的补语,进一步说明情况,给你个例子
eg.The animals you eat had to spend their lives crowded together in tiny spaces.
这里类似的,crowded是为了进一步说明动物的生活状况,所以用过去分词形式