let me ask.... you said that they were using ac as the process, or the machine was on grid power.... when using dc process, the electricity will go exactly from work to rod or rod to work... when using ac, anything goes... anyone thats ever had sweaty gloves while tigging aluminum and touched the filler to the work knows exactly what i am talking about.

being on or around the work while it is being welded with ac process is a hazard... i use ac only to tig aluminum and to get around magnetic arc blow..... because arc blow, blows!