It literally means "good so far", but context is key here: if you'd normally expect an unreservedly positive response, then "so far, so good" can be interpreted negatively. For example, when I get in the elevator at lunchtime and ask a co-worker how it's going, the default polite response is "Fine". If they say "so far, so good", I can interpret that as "the storm hasn't hit yet, but there's the whole afternoon to go".

Another interpretation is "I'm not done yet, let me finish"...I would guess that is what the tech was probably trying to say to your wife in this case. And it was not a good way to say it, considering the circumstances. 

Does "so far, so good" carry a negative connotation?
How would one look for and confirm existence of a graviton?

Someone was speaking to me about perhaps one day discovering the graviton, but to me it seems unlikely, although I'm young and essentially quite naive, so am coming to you physicists to ask 


What actually is the likelihood of finding it? 
How would we find it?

