I survive because there is nothing stopping be from surviving in your post.

A cleric uses Divine Intervention and asks their god to kill you.

I AM the god.

Tarrasque.

Cthulu.

You are faced with defeating Technoblade in MC (he’s still alive in scenario) and if you lose, you die.

I attempt to beat him in a Potato War, attempting to knock the crown off his head. I'd simply just do what both Squid and Techno did in the original.

You are held in a Jigsaw trap. (Imagine any Saw or Spiral- From the Book of Saw trap).

Held, not trapped. I quickly escape.

Cthulu’s wrath is unleashed upon you.

I survive because Cthulu doesn't have a stat block and the DM always goes by raw.

A level 20 barbarian is hunting you, and your a commoner.

Problem is, the barb is big and stupid. I can just hide under my bed.

Every single creature with a stat block is attacking you.

I survive because they keep getting each other's way and the timing of their attacks are comically bad. (The dragon with fire breath goes at the same time as the dragon with ice breath. The wyvern accidentally snatches the giant eagle out of the air instead of me as they attack at the same time, etc.)

You open a forbidden book in an ancient library, causing you to go mad and run directly into a deadly trap.

I’m an ooze and so cannot go mad and just absorb the trap.

You are ground zero for 1 billion wizards’ fireballs

I cast Antimagic field centered on myself.

The DM is trying to kill you.

Gee golly, my direct message is trying to kill me? Good thing I can block it.

Tiamat is going to breath fire on you in exactly 0.000000001 milliseconds.

Unfortunately i have a shield guardian, I’m a level 20 rogue, and the DM is using dice that always roll ones and twos.

you are being attacked by approximately 2,0000 sprites and 1,000 Hags, and they have a surprise round.

I am the mighty Pun Pun!

The mighty Pun Pun attacks you!

I cast Gate and go to another plane of existence.

A sorcerer just used a couple mage hands to put a bag of holding inside another bag of holding right before slipping through a gate.

The astral plane is liveable.

You've been put in the astral plane because some jerk sorcerer placed a bag of holding inside another and now a Spelljammer crewed by malicious liches is coming at you. 

I cast prismatic wall as a sphere above them, and then cast reverse gravity over and over again on them so that they fly up and down through a prismatic wall twice per reversal

You are subject to prismatic wall and reverse gravity in a tandem of death.

There is only one Reverse Gravity spell, which is propelling me away from the Prismatic Wall

You are in a blank, infinite demiplane that has just swapped places with the rest of the multiverse. This swapping has killed all but you. There is no other organic matter to subsist on. All spells fail. You have no equipment. You are mortal.

How can I be mortal I am William Afton therefore I never die!

You are in the center of the Gravity Sinkhole spell, having access to no magic, and an Ancient Red Dragon is being pulled in toward you...

But I am Tiamat so I’m fine

You are a red dragon being pulled closer and closer to Tiamat 

But I am her most loyal priest so I am fine.

You are a human commoner in the far realm armed only with a club and no plot armor.