Having the people blurred is not an issue and something you wont get away with as you need to use longish exposures. If the exposure is too short you will only capture part of the scan. If you have any sort of manual control of shutter speed try around 1/10 - 1/30 sec. Much slower than this and you will need a steady hand or tripod.
To get a good laser shot with people properly lit need a bit of trickery - normally done with a long exposure to ensure the lasers are captured and manually firing a flashgun to illuminate the crowd. Tricky but possible.
See my self portrait here http://www.stanwax.plus.com/laser/selfp2.jpg- not brilliant but the same idea. I was kneeling on the floor and was holding a flash gun that I manually triggered (whislt pointing it at a white cupboard to my right to reflect the light)
Rob