Poseidon ending explained (spoilers)

[Mai Lan]

The last seven make it to the propeller tubes. Nelson goes to open the door to the propeller tubes and is shot back by the air pressure. Robert decides that he needs to go and shut them off. Christian wants to do it since he is younger and can probably hold his breath longer. As he is talking to Jennifer, her father (Robert) dives down and goes without telling them. Meanwhile, Conor is trapped behind a fence-like wall and his mother and Dylan try and rescue him. Just as the water is over his head Dylan saves him and they head for the group by the propeller tubes. Several minutes pass and Robert doesn't return. We go below the water where Robert is and he is running out of breath. As he runs out of breath he pushes a button that reverses the propellers. He then dies. The group figures out what he did and Dylan throws something in the tubes to make the propellers explode. The group gets out safely, and they jump off the boat and climb in an inflatable raft. A couple minutes later rescue helicopters arrive and save the six of them.