Death Valley is very safe in every way other than heat exhaustion/dehydration. I did 6 nights there earlier this year doing most the 4x4 trails, back country camping and hiking 100% alone. Not once at all did I ever feel unsafe. The biggest knife I had on me too was a kitchen paring knife to make dinner with.
Even though you are allowed to carry a firearm in DV it is illegal to discharge that firearm for any reason what so ever.