When you look at a well-written scene, you should be able to state in summary what the events and emotions are.
What makes an event in a scene?
The sum of the overall action of a scene--"what happens" --is the event. When we state what happens on a moment-to-moment level, we are naming the actions. When we state what happens globally, we are naming the event. Actions + actions = event.
This may seem elementary, but often, young writers get caught up in describing what characters are thinking and feeling, and nothing much happens at all. Or they try to keep the action popping, like a movie, and it's all just a jousting match in which nothing really gets decided or changed.
Event does not have to be spectacular, but it does have to be interesting and meaningful. It has to make the story go somewhere.
Situation ---> line of action ---> new situation
The scene should bring us in, let us know what is going on, involve us, and let us go.
Distinction between pulse and tension
Pulse is emotional, an attitude, a state of desire or need. Tension is built from action; it arises from pulse, but it must be created through conflict, whereas pulse is a kind of "steady state," awaiting the trigger to escalate it.