If someone is stabbed or punctured by a sharp object, leave it inside.
Do not – absolutely do not – try to pull it out! Leave the object in until help arrives.
Pulling it out will only double the damage: the object can considerably reduce and stop the flow of blood by exerting pressure on the injured area. The moment you pull it out, blood flow is likely to increase.
"People having seizures cannot swallow their tongue. Do not put anything in their mouth."
It's not that people actually swallow their tongue, it's that their tongue will rest in the back of their throats restricting their ability to breathe. People have heard this and misunderstood what was actually happening and spread misinformation for decades. So then things like this come out without actually addressing the truth or the root of the phrase. Your tongue isn't going to rip out of your mouth and go down your throat. It can rest in the back of your throat and choke you to death. That's what they are saying when they say "swallow your tongue."