Hello! If you already have Eric's red wristband, you should be set. I think the game might have a bug in which if you buy it from Boris it will screw up the mission.
If you don't have his red wristband, one of the crates at the center / near the end should be the one. You don't have to wait after it prompts that "you have found nothing". Just wait for the character to reach the crate.