Carissa casts Detect Magic. There aren't invisible people in the room right now, or if there are they're concealed against Detect Magic which would be a sensible precaution now that Keltham probably has it, but that's not really the point. Then she stands up and paces the length of the room, staring at things. 

Carissa who had just learned this information and wasn't hiding anything, because a god dropping five cleric levels on Keltham is communicating that He expects Keltham to need them. Carissa is also, separately, scared, but that's unrelated. Though maybe helps with her acting. 

Carissa casts Detect Magic. There aren't invisible people in the room right now, or if there are they're concealed against Detect Magic which would be a sensible precaution now that Keltham probably has it, but that's not really the point. Then she stands up and paces the length of the room, staring at things. 

Carissa who had just learned this information and wasn't hiding anything would be scared, because a god dropping five cleric levels on Keltham is communicating that He expects Keltham to need them. Carissa is also, separately, scared, but that's unrelated. Though maybe helps with her acting.