Sister,
Find Anghel and tell him to drop everything and go to the sacristy. He's to reinforce the doors and board up the windows. Make sure there are no witnesses to your conversation and tell him to be as discreet as he can.
Mention this to no one, not even other sisters. Lie if you have to.
I'm sorry to lay this on your shoulders but we need to take certain precautions. Our convent is a kettle set on hot coals – it's only a matter of time until it boils over.
Bernice