For my story, a woman is subpoenaed to testify against a gang member who is arrested and being prosecuted. The rest of the gang, do not want her to be a witness, and she has a cop watch her house at night. I want the cop to be knocked out, or incapacitated somehow. So for the rest of the night, she is forced to defend herself and her home on her own, with more available cops to watch her, since the police cannot send anymore, or at least have any more stay the whole night, after investigating an attack on her house. But how can I write it so that the cop will be incapacitated for the rest of the night, but be okay the next day pretty much, so he can fit back into the story later, when I want to use him again? Is there any type of injury that would work for this effect?