I am writing a character monologue from the perspective of Boo Radley after he saves Jem in To Kill a Mockingbird. What tense should I use?It...

Even though you are communicating the action that happened
after Boo's encounter with Bob Ewell, you do not necessarily have to use a past tense
monologue. You could have Boo describe the events as if it were happening at that
moment.

"I am watching the children pass through the
darkness, and I see a man stumbling after them. I wait until they nearly pass me, and
then I see that he is about to attack them. I move
forward..."

You could create a monologue with Boo giving a
statement to Sheriff Tate where he describes what happened from his point of view. I
think a past tense monologue would be easier, but a use of present tense might be more
interesting and challenging.