Why YSK: Even if you don’t own a gun, there is a chance you can encounter one at the home of a friend or family member. These are the four core rules of gun safety, but the same can be used with airsoft/paintball guns, nerf or even chemical spray bottles!
First, treat every firearm as if it were loaded. Even if it was clear the last time you saw it. If looking at a gun with someone else and they assure you it’s not loaded, you can respectfully ask them to clear it in front of you before you handle it yourself.
Never point a gun at anything you are not willing to destroy. Pretend there is a lazer beam coming from the barrel. Don’t let that “beam” point at anyone. That is known as “flagging”. In nearly all cases keeping the barrel pointing down between your feet is a good move.
Keep your finger off the trigger until you are ready to fire. This includes the whole trigger guard area. Most people keep their finger on the frame well above the trigger guard, pointing their finger in the same direction as the barrel. This is known as “trigger discipline”.
Finally be sure of your target and what’s behind it. Bullets can still travel a long way even after they pass through a target. If you are target shooting make sure there is a solid backstop. If in a real life situation you must positively ID the threat, no shooting at shadows or noises.
Basically, if pressure from a stream of liquid is high enough, 100psi/6.8bar is enough to hurt a person, it’ll break your skin and there’s your injection; this is why for, say, anyone working in the diesel mech field, for example, never touching a leaking fuel line is rule #1 because of the immense pressures those are typically under, which will result in a hydraulic injection injury if ever touched, basically as Bytemeister already pointed out.
Industrial paint guns or grease guns also operate under high enough pressures to cause an injection injury.
TIL that’s a big no thanks from me. I’ll stay far and away from any leaking fuel lines.