A good amount of Redditors pointed out the subtle occurrences that look relatively harmless but call for a serious emergency response.

Often, these tips involved going straight to the hospital. But knowing when it's time to go there is often the pivotal variable in saving or losing a life.

Don't Count Anybody Out 

"If people stumble for no reason and sound drunk but haven't had alcohol, ask them to smile. If it looks weird/ one side is drooping, get them to a hospital ASAP. High chance it is a stroke."

"Plus people of every age can have a stroke."

-- Zuckerschneggle

Know What to Look For 

"The symptoms of a heart attack are slightly different for men and women. This is one of the reasons women sometimes get diagnosed too late."

"Men: Cold sweat/ nausea; Chest pressure/pain; Shortness of breath; Pain in arm(s), back, neck, jaws, stomach"

"Women: Fainting/ extreme fatigue; Chest pressure; Shortness of breath; Upper back pressure; Light-headedness/ dizziness; Pain in arm(s), back, neck, jaws, stomach"

-- Veni_Vici-Vetinari

YOU WILL NOT GET IN TROUBLE

"If you are taken to the hospital and the doctors ask you if you have taken any drugs don't just think about the illegal stuff also tell them if you've had small things like Advil or Tylenol it could save your life." -- Atomicwaffle117

"Frankly this needs to taught in schools. I've known people who took stuff and didn't tell the doctor's, they either went into withdraw which prolonged there stay, or the doctor's have them stuff which interacted with drugs and they nearly died cause of it" -- xxluisvrewxx

Warning Signs 

"If your vomit looks like coffee grounds, you may have internal bleeding. Head straight to the hospital." -- Long-Cupcake

"Additionally, this kind of internal bleeding is further down the digestive tract and has a higher chance of being a more serious issue."

"coffee grounds means that the blood has been digested by your stomach. if it was just a tear in your mouth or esophagus (like from vomiting too much) it would be bright red." -- elaerna

Other people offered advice geared toward sudden emergencies that strike out of nowhere. These are the situations where the right knowledge, held deeply in the brain, can turn you into a first aid life-saver.

Hopefully you'll never use these skills. But it's best to be ready.

Get Low 

"Crawl out of a burning building, breathing as close as possible to the floor as you move."

"Toxic smoke rises while air remains more breathable nearest the floor."

-- Back2Bach

Not Over Yet 

"There's something that's called gasping. It's the fake breathing that occurs when you're performing CPR on someone that has water in his lungs (i.e. because of drowning). It looks like a fish that's trying to breath when it's out of water."

"The person is not back alive then, and you should not stop the CPR."

-- SilverStory4502

Quarterback the Response 

"In an emergency around any other people, be intentional and specific with people. Do not shout into the void 'someone call for help!!!' "

"Make eye contact with someone, make sure they know you are talking to them, tell them what you need: 'Sir in the blue shirt. Call an ambulance.' 'Ma'am with the green jacket, go ask the barista for a clean towel.' 'You with the hockey mask and machete, watch this baby!' "

"Studies have shown that the assumption that someone else will do something is ingrained within people and often they will not help without specifically being talked to."

-- Goosfrabbah

Finally, some people took the preventative approach. They highlighted either moments or longer term dynamics that clearly indicate a looming crisis.

Knowing what comes next can help prevent things from ever getting there.

Deprive the Oxygen 

"Don't pour water on a burning pan/oil/grease in the kitchen, cover it with a damp cloth or towel. Water will make it explode like a bomb."

"Same goes for gasoline I believe - the burning gasoline will just float on top, still aflame, but now spreading more easily to something else flammable."

-- bodhi85uk

Ya Never Know 

"If you have to eat crickets or similar insects, chew them. DO NOT EAT THEM ALIVE. They have spines on their legs which can cling to your throat and are very difficult to remove without a decent amount of force (i.e. you cant "shake" your throat like you would your hand to remove them)."

"If they block your wind pipe, you'll asphyxiate."

"I used to work at a pet store, I've had to explain this to quite a few people who wanted to do "Fear Factor" parties or dares or pranks."

-- AzoriumLupum

Counter-Intuitive Warnings

"If one of your depressed friends suddenly starts acting really happy or peaceful, don't leave them alone."

"When suicidal people have a plan and are about to kill themselves, it can make them feel relieved which can make it look like their depression is getting better."

-- mylifeisathrowaway10