Inferred Mood and Action from Stage Directions

In a dramatic script, stage directions play a pivotal role in conveying the intended actions and emotions of characters. Consider the following excerpt from a fictional play:

Stage Directions:
As the clock strikes midnight, JANE enters the dimly lit room, clutching a letter tightly in her hand. She pauses, glancing over her shoulder anxiously, before stepping further into the room.

Based on this excerpt, what can be inferred about the mood and action of the scene?