Hi there,

if you ask yourself, how to open the Timed Chests.
Here is the answer.

The timed Chest, will be open after resting at the Campfire. After the rest you have only 10 - 30 Seconds to reach and open it.
Make sure to clean the way. (My tip, use the perma-death from the Relay.) Open all nessesary Doors or path. Break walls, doors or obsticals if you must. At last, choose the shortest way to the Chest.
An last Tip: Choose your resting position wisely. You must start immediately after rest. So make sure, your restingpoint is in the chestdirection.

I hope this tip will be usefull.

Good luck.