I'm going to be there - with bike. Not sure if challenging would be the right word, but partaking could be better!

Note that the max gear is likely to be revised slightly downwards to approx 101 inches - using a standard 700 x 23 wheel, then 53 x 14 or 50 x 13 is probably the biggest gear allowed. There is a small difference in those 2 respective gears, but not likely enough to make a difference in end result.
Put another way... a 500m event would be just 61.4 pedal revs in one gear, and 62.4 in the other.
If you can spin out at approx 180rpm, it will all be over with in 20 seconds...
Something to practice in the next turbo session???
Paul