Near the beginning of the movie, when Rick and Evelyn open the chest containing the Bracelet of Anubis and take out the bracelet, the tomb they're in begins to flood. Rick throws the bracelet back into the chest and they run for their life. Alex is the next person to open the chest. When he opens it, the bracelet is perfectly in place.
Yes, they probably would have- the chest was cursed, and the whole flood happened since they opened the chest when there was a warning written on it: "Whoever disturbs the Bracelet of Anubis will drink from the waters of the Nile" or something like that.
If you listen closely when Alex puts the chest down it makes a "cling" noise. This noise is the bracelet opening by itself and in doing so it probably positioned itself back into place. This is a magic bracelet.
If you actually look, the bracelet is not in exact place. When the box was first opened, it was straight in the box. When Alex opens it, it's diagonal. Hence, it was only moved when it opened it'self up.
Ok, I just watched that scene... Alex does open the chest with the key. Before that, when you hear the clink, it shows the chest from the back and Alex turns around to look at it. Then when the camera shows the chest from the front, it's still closed. The clink might have been the bracelet inside the chest, because the box didn't open by itself.