Immediately after, one of them lifts the glass from mouth and gulps down the entire drink which feels pretty cold due to so many ice cubes. Immediately after drinking, the bars holding his hands are lifted and he is set free. Seeking that he might die with the poison soon, he tries to help the other person. After about half an hour when he is not able to set the other person free, he acknowledges that he managed to survive. Both of them thinks that it might be a hoax warning after all and thus the second person drinks his drink as well. The metal bars are lifted and he is set free but he dies after a couple of minutes.
How is this possible that only one of them died after drinking the same drink? (The poison was in both the glasses)