"Go through the left door and get ready to defeat Revas (this time for good! ;-)). Wait for this duel to commence and start RUNNING towards a locked door . Use the panel to your right to open the door, unlocking access to a large elevator shaft.
Once you’ve opened the door retreat towards one of nearby pillars, however notice that you won’t be fully protected against Revas and her attacks. Focus on attaching a single explosive bullet to her body, but don’t detonate it just yet.
Wait for Revas to stop directly in front of the elevator shaft you’ve opened not long ago. Detonate the charge and start running towards her. Attach a few other bullets to her body and this time detonate them right away. Once you’re close enough to Revas choose the blades from your inventory and finish her off. You have to do this before she’s ready again to fight Riddick. If you’ve done everything according to the plan she’s lose balance and fall into the shaft. Sit back and enjoy the ending. Congratulations for finishing the game!"