To break into a safe in GTA 5 Online (specifically in the Stash Houses event), the process is as follows:
- Find a Stash House marked on the map and approach it. Make sure you do not have a wanted level before entering.
- Break down the door to get inside the Stash House.
- Inside, defeat all the armed dealers protecting the safe.
- Look for a yellow note somewhere in the room (usually on a table, a wall, or a pole). This note will have a six-digit code.
- Memorize or write down this six-digit code.
- Approach the safe and enter the six-digit combination carefully. Use the controls to select each digit, ensuring you do not press confirm until all six numbers are entered, to avoid error.
- Once unlocked, open the safe and take the contents.
- Escape the Stash House area quickly, as reinforcements will arrive outside.
You will either receive $30,000 or supplies for your in-game businesses as a reward after the heist.
This method applies to the Stash Houses in GTA 5 Online's Gerald's stash event, and it involves locating the code within the house rather than guessing or forcibly cracking the safe physically.