Sounds like fun The first helo dunker I did (circa 1986), we had seats and were all strapped in. They did the crawl, walk, run thing, which meant you needed to go through the process multiple times. 1) any window/door, eyes open; 2) any window/door, wearing opaque goggles; 3) (everyone) main cabin door, eyes open; 4) (everyone) main cabin door, wearing opaque goggles.

I tended to take my time and wait for the feet to clear. Being able to relax and take your time under water is huge. Once panic sets in your clock starts running much faster.