It seems fairly direct. Sure is informal, but it isn't rude to use it in most contexts - and there seems casually friendly to me. I'm guessing they may have left for any number of reasons. "Go" makes it more of a command there...I suppose you could soften it by saying "let's go for..." or "let's do". Even still I don't see anything that would read as rude in that phrasing.
Also tech support are used to being yelled at by customers, they should have a high bar for what constitutes rude. One time, I was my normal cheerful self with a tech support guy, and he got sort of emotional at the end of the call, told me I was the nicest customer he had ever spoken with...which again demonstrates how horrible most people must be with tech support. So don't give it a second thought.