Loads of people on this forum are assuming it is the water that the three men are chasing Adam for. I don't think so.
Firstly, The bald guy says 'you know what we want' so when Adam is running away at the beginning of the trailer he clearly wants whatever they want just as much as they do. So when he gives them the water he would surely put up a fight rather than simply giving it away.
Also, the three men are suprised when they see the water, 'water!'. If this was what they wanted they would not act so surprised.
Secondly, after realising the floor was glass he threw the water to trap the three men but doing this he knew he would lose the seemingly precious water and he could have simply given the men the water and they would no longer need him anymore and he would walk free.
Perhaps there was something more important in his bag that he was protecting ( what the three men want) and because he knows the water is in VERY high demand he knew the men would take the bait and fall to their death.
What do you think? If you agree what could be in the bag??