with the bag in their possession是修饰后面both men...这分句的状语,要用逗号分开.
如,With two apples in his hands,he left.
但,在句末,不用逗号分开.
He left with two apples in his hands.
原文也可以写做:
In the struggle,the strap broke and,both men started running through the trees with the bag in their possession.
And后面的逗号,表示停顿语气.