The total energy in the beam is 724 MJ (173 kilograms of TNT) (energy stored in magnets are 10x this) That is a bomb big enough to take out a school.
It would be hard to get your hand into vacuum, but imagine a space suit arm attached to a sandblast cabinet.
The beams energy would hit your hand in a spot d1mm. It would most certainly deposit all its energy there until that part of your hand became a vacuum. Probably similar to a laser knife. In addition, your flesh that obstructed the beam would give off a lot of radiation as it burned away. Imagine Hiroshima 1km away x10^8 on that part of your body.
Every proton would not hit something in your hand on first encounter, but if it missed, it would just loop around, and hit on a later time. The result would be the same. In a short time, your hand and your space glove would have a hole through it. More likely a straight cut from where you put it in. Anything nearby would be exposed to a good dose of radiation as these collisions would be quite "dirty".