Your scene should climax both in terms of plot and emotion.
It should start with a protagonist with a scene goal—what he wants to accomplish in that scene. His emotional starting point is determination, a plan of action.
Next, you throw obstacles in the protagonist’s path so he can’t get his goal. This builds frustration, anxiety, sadness. Up your character’s emotional state.
Build the obstacles to become more and more difficult. At the same time, build the character’s emotional intensity. Go from frustration to anger, or anxiety to panic, or sadness to depression.
At last, deliver a final blow—a disaster at the end of the scene. This will also be the height of your character’s emotions. Ride it for all it’s worth.
By building the character emotions, you also build your reader’s emotions for the character. Take your reader on an emotional ride, and they won’t be able to stop turning the pages.