In the last Fortnite update v22.10, Holo Chests were added to the map. Much like the game's Vaults, they require keys to open and contain loot of varying rarity. Seeing how popular they are in-game, Epic Games has come up with a clever challenge for players to complete in week four of Chapter 3 Season 4.
While the challenge's description is rather vague, based on what's written, players will have to open a "Lock with a Key", which could imply a Holo Chest or Vault, as well as a "Safe" in a single match. Since the developers can be deceiving at times, interpreting the requirements for this challenge can be tricky. To be on the safe side, it's best to look at all possible options.

Master the game with our Fortnite Interactive Map v33.00 here!
How to open a Lock (Holo Chest/Vault) with a Key, and a Safe in a single match in Fortnite - A step-by-step guide
Follow these easy steps to open a Lock with a Key and a Safe in a single match in Fortnite Chapter 3 Season 4:
- Land either at Fort Jonesy or Rave Cave
- Secure basic loot and gear up (ensure that shields are maxed out)
- After securing the POI, start searching for Keys
- They can be found in normal, rare, and Chrome Chests as well as Supply Drops
- While searching for Keys, look for a Safe and open it to complete one part of the challenge
- After a Key has been found, proceed to a Holo-Chest and open it
- Note: If the challenge requires players to open a Holo-Chest and Safe, it should be completed at this point. However, if the challenge requires a Holo-Chest and Vault to be opened in a single match, a few more steps will have to be followed:
- After opening a Holo-Chest, players need to find another Key
- Once it has been found, they have to rotate to the nearest Vault to open it
- Those landing at Fort Jonesy can open the Vault at Seven Outpost VII, while those landing at Rave Cave, can head to the Vault located in the POI itself
- Note: These Vaults require only one Key to open
Keep in mind that since the challenge is rather vague and doesn't specify the exact requirements, following these steps will be the best method for players. Whichever way the challenge goes, players will be able to complete it with ease.
Which one is better to open in Fortnite Chapter 3 Season 4: Holo-Chest or Vault?

Weapons play a vital role in-game, and there's no doubt about that. Having weapons of the highest rarity in Fortnite makes a major difference, but using a Key to open a Holo-Chest for just one item is not a smart move.
Since Vaults contain a lot more loot and items that can be used for different purposes, it is a better choice when a player finds a Key. That said, this will depend on player to player.
For those who enjoy a more aggressive approach to gameplay, a Holo-Chest might just be the better option. On the flipside of things, when playing with a team, a Vault may just be the best source of early and mid-game loot in Fortnite.