Car Mai saw in her dream below the street outside of Cas' shop:

i.pinimg.com_564x_70_ce_f9_70cef94a62f5b45fd2f7f36e306f296a.jpg

Chicago Department of Public Works (DPW) sewer workers:

i.pinimg.com_564x_2e_27_e1_2e27e1c6e24c56606e2e573d3d63cdbf.jpg