If you are getting symptoms like that you definitely are getting overexposure to the fumes off the flux and the brass.   Brass smokes a lot and its not good for you at all......yall all have a sit down with your instructor and talk this situation out.   See if together you can identify the causes and then brainstorm some solutions with what you have to work with to keep everyone safe.   It is bad work practice to live with exposures that cause harm and they have no place in the modern working world....so you certainly should not accept them in a learning environment.

The chugging of milk is more or less related to zinc oxide(??) poisoning from welding on zinc plated materials...I would imagine the same could be said for cadmium which is far worse but causes the same kind of symptoms initially.   It is not a urban legend.... it actually does help.  The biochemical process by which it does work I have no idea....but it lessens the symptoms quite a bit if it is ingested early enough.   I know two former coworkers who where hospitalized from welding on zinc plating....we were working under very bad conditions and everyone would drink milk after exposure...it helped, but I have no idea if it truly medically staved off the poisoning or simply treated the symptoms. Milk is good at absorbing things during cooking like the flavor of too much salt...so perhaps it can absorb some of the poisons and help carry them out of the body??

Since we are on the subject of welding myths sort of.....    If you get a flashburn in your eyes,  taking white potato slice and then smashing it up inside a clean rag and then squeezing the juice from the rag into your eyeball does give a bit of relief to the pain.  THe laying potato slices on your eyelids did not do squat for me but the juice worked ok.   The pontiCANE at the hospital worked fabulous tho....made the potato pale in comparison LOL!