Moderating a Usability Test

My experience moderating a test went nothing like I had imagined. We ended up having a major technical issue when he attempted to order, in fact as soon as we hit the site. However because I was wrapped up in the tasks and wasn't in a good location to read the screen I didn't notice it at first.  

After that, my test subject struggled to find where to begin his order and I immediately I wanted to jump in and show him where to go and how to perform the task. I refrained from doing so, but it was a more challenging the longer it took.  I began to feel a bit flustered and had to mental calm myself as we continued.

Eventually he made it to the ordering page and got a "technical difficulties" page and was unable to complete the portion of the test where the ordering was required.  It seemed to me that he was frustrated with this and with good reason.  I can't help but think that a complete failure is among the worst technical results we could encounter during a first time moderation.  it totally caught me off guard. However, at least the team would now be aware of an issue with outages.  

I think on the whole I did OK. About what I'd expect for a first time moderator exposed to a situation like this one.  There were some things I did pretty well with, but others I should definitely work on. I need to be sure to ask good follow up questions.  I tended to ask what first came to my mind, even if it wasn't a very good question. I also need to present a calm demeanor.  I was nervous and I think he probably picked up on that. 

To say the least it was an eye opening experience.