"It wasn't a very nice thing to see, but in some ways it was quite good for the old peace of mind because it can get quite dodgy and hairy out there," the former Olympic rower said.
"It definitely provided a good test that it is actually a lot more stable than anyone thought. With the normal pedestal grinding you're kind of only holding on with two hands. We're clipped in and sitting on a seat and holding on with our hands as well so we have five points of contact, which really helps keep you nice and stable."
Sullivan said the team have had a few "dodgy" moments during their testing programme in Auckland, but last week's incident was the "worst one by far and hopefully the last".
"We really need to keep it in one piece, we can't afford to have any major stuff-ups, it just takes too much out of the team. A lot of work goes in to get it fixed and ready to go the next day," said Sullivan.
While the nosedive scare provided the team with helpful information, the biggest learning experiences in Bermuda came in last weekend's practice racing. Having spent much of their build-up in Auckland with only their chase boat to spar against, Team NZ's involvement in the final day of the third official practice racing window gave the team a much-needed test under race conditions.
Sullivan, who up until last weekend had never been in a yacht race before, found the experience particularly valuable.
"It was definitely a bit more intense, every one is really switched on and really locked into what we're doing. We didn't have the best of races, but we learnt a lot, which was really good and just to get out there and really cement that understanding of what you need to do and what the boat needs was really helpful."
The next official practice racing window will be held from May 16-20.