Than go where men wait me and dance at the King's. (12)
It's pretty clear from this line and others that this lady's life revolves around men. She's used to having guys interested in her, to being beautiful and appealing. Her life at court is about beauty and fashion and competition with the other lovely ladies who "dance at the King's" (48).
To carry pure death in an earring, a casket, A signet, a fan-mount, a filigree basket!
Like a pistol in a handbag, this woman's accessories are all about deadly force in a demure, ladylike package. As this poem is going on, she's in the dirty, smoky world of the laboratory, but she keeps reminding us that she's more accustomed to the glittering world of the royal palace. There, everything depends on how pretty she can look, and her fans and rings and baskets are her everyday weapons in the war against other women.
And her breast and her arms and her hands, should drop dead! (24)
Our speaker pays a lot of attention to other women, noticing every part of their bodies. When she imagines killing off her rival, she doesn't just talk about how she's going to fall down dead, she imagines the different parts of her body being destroyed. There's definitely a Mean Girls vibe in this poem…only with fewer funny, catty comments and more hideous death. (Although, maybe Lindsay Lohan would be a good choice for the main character in a movie version of "The Laboratory." We'll leave the casting to you.)