The best buy in liability insurance to cover an incident, is to contact your insurance agent who sells your home owners insurance and inquire about an umbrella policy.
In todays market $ 1 million is around $ 125-150..$ 2 million not a lot more.
If you are an NRA member, there are policy's available thru them but not as cheap as an umberlla policy.
I recommend the Umbrella policy to all students in my CCW courses....it is a natural if you choose to CCW.....and a critical incident happens !
Always good to have a plan !