What are the Reasons for deadly force?

1. Self defense, and defense of others. 2. Serious offenses against others.3. Protecting assets vital to national security4. Protecting assets not vital to national security but inherently dangerous...

In general, "less than deadly force" or "less lethal" are terms that refer to use of force would not be normally expected to cause death or serious bodily injury. Some examples are tazers or stun...

Yes there is

Yes under certain circumstances. Check the Texas Penal Code for specifics.

1) You are asleep.2) You are in an anti-gravity machine.3) You have left Earth's gravity behind via plane or rocket.4) You have ingested powerful hallucigens.