In Scene 2, Macbeth describes his surroundings by saying. "Light thickens, and the crow/ Makes wing to th' rooky wood." How can these remarks also be seen as a metaphorical commentary on the events of the play?

In Scene 2, Macbeth describes his surroundings by saying. "Light thickens, and the crow/ Makes wing to th' rooky wood." How can these remarks also be seen as a metaphorical commentary on the events of the play?
I have another question. In Act I, Lady Macbeth, not wanting to feel regret for killing Duncan, calls upon the spirits to “make thick” her blood and to “Stop up thwacks and passage to remorse”. She also requests that the “thick night” cover her “in the dunnest smoke of hell” so that no one is able to see the murderous deed she plans to commit.

Did Macbeth ever make a similar request?(like one to help him follow through a murder... or for him not to feel regret)