This mode can only be unlocked by earning the best ending (ending 'A').
However, to save survival mode, you must save the game again in Overtime Mode
(in the hideout) and either die (save and quit) or clear the game (harder than
it sounds if you're not prepared). If you opt to go into the main menu for
this mode without saving, you need to go through 72 Hour Mode again.

how do u get ending A because I did all the cases and was on the helipad but I got the one
were the piolet gets eaten while lookin in the binoculars

Talk to...What's her name? In Carlitos Hideout at 10:AM,Then arive at the Heliport at
12PM.

btw if u beat overtime you get infinite mode which is just surviving for as long as
possible

plz watch porn

beat the main quest thing