Shut the Door to Catch the Thief
If you have the chance to completely capture the enemy then you should do so thereby bringing the battle or war to a quick and lasting conclusion. To allow your enemy to escape plants the seeds for future conflict. But if they succeed in escaping, be wary of giving chase.
Many many jobs ago, there was a development environment. And within that department, there were several programmers. One of them was a whining pain in the butt. All she did was complain about the status of the project, the direction and lack of skill of the management, how she didn't feel needed in the project, and how she wanted to manage things herself and how much better things would go if she did. Management had a chance to fire her when she filed false allegations against a fellow employee. But they didn't; they thought she could turn things around if they "gave her a second chance". It was a poor decision on their part. She continued to gossip, "network", ingratiate herself with other department heads, and cause dissension. Over a period of months, she consistently badmouthed her boss, but in a way that could not be directly attributed to her. Eventually, her boss found the opportunity to get rid of her and other malcontents during a period of "budget problems", but he had taken a lot of damage to his professional reputation in the meantime.