Answer to scenario A.-The police is subject to serious injuries. Being a police officer is a risky business everywhere. Police officers must be prudent and always be alert. However, you can see on the news that criminals hurt and even kill police officers. Taking into account that biting can be something that criminals can do sometimes it is necessary to put a gag on criminal's mouths.
Answer to scenario B.-Stress can be dealt in many forms: Ludic activities like a bowling contest with work colleagues or a football game are a good idea. Music can be also a great way to relax. Another way to relax is dancing. Learning to dance tango can be a lot of fun. The best strategy is praying because God exists and if you ask with faith something, the Lord is going to give it to you. In this case you can ask God for serenity and calm.
Answer to scenario C.-When dealing with blood investigators have to wear masks and gloves and be very prudent when they are managing evidence. Fortunately the procedures when dealing with infected or hazardous materials, situation or evidence are very clear and specific.