Genre: speculative fiction
Calvatica

Father Anna stood motionless in the dark, her hand in the top drawer of the prefect Cardinal’s desk. No one should be in the building tonight, everyone’s required at Mass, she thought, listening to voices murmuring in the hall outside the office.
Once the voices passed and silence returned, Anna’s fingers tightened around a key. Tonight she would find the proof she needed. Tomorrow, she would go to the Camerlengo with more than just figures from her auditing of the Vatican’s accounts. After tonight, she would know exactly what was happening in the catacombs below the Pope’s apartments.
Anna hurried to a door that was to the right and behind the Cardinal’s desk. It was narrow and decorated with a relief of Jonah staring into the toothed mouth of a whale. “God’s will be done,” she said as the key clicked in the lock and the door swung open.

Also, I'd like a hint at Anna's emotional state. Fear? Anticipation? Anger?

Suggested [deletions] and ADDITIONS:

[Father] MOTHER Anna stood motionless in the dark, her hand in the top drawer of the prefect Cardinal’s desk. No one should be in the building tonight, everyone’s required at Mass [usually this is lower case], she thought, listening to voices murmuring in the hall outside the office.

Once the voices passed and silence returned, Anna’s fingers tightened around a key. Tonight she would find the proof she needed. Tomorrow, she would go to the Camerlengo with more than just figures from her auditing of the Vatican’s accounts. [WHAT WILL THAT BE? IF SHE KNOWS, I WANT TO KNOW TOO.] After tonight, she would know exactly what was happening in the catacombs below the Pope’s apartments.

I think what is taking place here is fine, but I believe there are better ways to describe it. I'd be tempted to start at this point (but with more about what she is feeling, who she is in relation to the situation, why she is determine to expose whatever it is):

Father Anna hurried to a door that was to the right and behind the Cardinal’s desk, but at the sound of voices in the hall outside the office, she froze and her blood ran chill. No one should be in the building tonight, everyone’s required at Mass, she thought.
Once the voices passed and silence returned, Anna’s fingers tightened around a key. Tonight she would find the proof she needed. Tomorrow, she would go to the Camerlengo with more than just figures from her auditing of the Vatican’s accounts. After tonight, she would know exactly what was happening in the catacombs below the Pope’s apartments. The door was narrow and decorated with a relief of Jonah staring into the toothed mouth of a whale. “God’s will be done,” she said as the key clicked in the lock and the door swung open.

But really, I would preferably start with the voices in the hall. For example (with some liberty, please... this is just an example to get my point across):

Father Anna heard voices in the hall. She stilled in the darkness, her hand in the top drawer of the prefect Cardinal's desk. Her heart pounded violently against her breast; her blood, chilled. Wary, she wondered who was out there, and if her plan would end before it even started.

They should be at Mass, she thought. {add more fearful stuff here... voices come closer and move away, etc....)

Or something like that.

Good luck.

Father Anna stood motionless in the dark, her hand in the top drawer of the prefect

Cardinal’s desk. No one should be in the building tonight, everyone’s required at Mass, she thought, listening to voices murmuring in the hall outside the office.
THE VOICES PASSED [Once the voices passed and silence returned], Anna’s fingers tightened around a key. Tonight she would find the proof she needed. Tomorrow, she would go to the Camerlengo with more than just figures from her auditing of the Vatican’s accounts. After tonight, she would know exactly what was happening in the catacombs below the Pope’s apartments.
Anna hurried to a door [ that was to the right and] behind the Cardinal’s desk. It was narrow and decorated with a relief of Jonah staring into the toothed mouth of a whale. “God’s will be done,” she said as SHE CROSSED HERSELF the key clicked in the lock and the door swung open.

just my 2cents

"Father Anna" gives me an "Oh, yeah?" and makes me not believe the story -- that is, I focus on the word choice, and stop thinking, "Anna's in the Pope's chambers preparing to explore the catacombs," and start thinking, "I'm reading a story and the author has an unusual word choice." That is, I've lost my suspension of disbelief, in the first two words!

When I read it (that is, when one of your potential readers was in that crucial first few lines), I thought: the author's trying to shock me. What's really happening is that the Church now ordains women, and although it would be easy enough to call her "Mother Anna" or "Bishop Anna" or something, he thought this would grab me. (If this initial reader impression is wrong, you could correct it then and there. If you don't, you'd better have some killer hook immediately, or you'll lose a reader. And if Anna is sometimes male, say, that would make a great hook!)

Start with Anna at Mass and have her sneak out. Perhaps someone asks her, "Where are you going, Father?" and Anna internalizes a thought process about being called a "Father"... maybe she really would prefer being called Mother, but the Church has decided that all priests are Fathers, all nuns are Sisters or Mothers. And so on. Just an idea. Then, it's not so shocking to the reader.

I know it's been done to death but the 'Father' thing didn't sit well with me and I was curious straight away as to why she was 'motionless'. I would start with the voices and a description of her fear at being found out. Maybe you could add a little context too, voices echoing off the long stone corridoors etc (if the place it made of stone).

I would have her desperately scrabbling for the key - she finds it too easily for something that's clearly important. You could create some suspense by making her search for it a little.

I also thought that you didn't need to say where the door is unless it's relevant and the same goes for the picture. What does the picture mean to Anna? Is it some depiction of her trials to come? or her fears of what she's getting herslef into? I would tell the reader straight out.

Lastly, I felt that using the word 'swung' with regards to the way she opened the door was too confident. 'Eased' maybe, surely she's still anxious about being discovered.

I liked the concept though, church corruption is and has been so rife throughout history that it's an ageless area to exploit.

I hope this doesn't seem too picky.

Good luck.

If the piece is shorter (1000 - 2000 words or so) then I would think about fast forwarding to Father Anna using the key to enter the catacombs or something along those lines and than recap how she got the key in a sentence or two. This way the sense of conflict is immediate. She's already broken the law and stolen an important object from a high ranking official based on her conviction that unsavory things are occuring in the catacombs. That in itself is a powerful statement without having to go into detail about how she snuck into the office.

Besides, the mysteries happening in the catacombs you mention struck me as the most interesting part of your beginning.

If the piece is a longer short story (3000 - 6000 wds)or even a novel length then the opening scene you have is fine. However, I do agree with the others that starting out with the voices in the hall or maybe even the door handle turning and Father Anna needing to find a hiding place for a moment or two pushes the good old conflict button a little better.

It struck me when making my observations that if I were to write this scene it would be very much longer.

My main thought was about atmosphere I suppose. I imagined a slightly damp, stone building, long passages, the slap of sandles against the wooden/stone floors etc and I wanted to feel this clerics fears. Pitching yourself against an institution like the church would be terrifying, especially from within. That's why I liked the premise so much.