captbod
AA is correct in saying that Sarin is primarily a non persistent type of nerve agent and it is normally delivered in liquid form or as a gas. I would argue however that the ability to move around completely unprotected would be unwise especially in the immediate aftermath of an attack. As AA said if there were large concentrations of liquid in the vicinity then the local area and the area downwind of the concentration would present a substantial vapour hazard requiring at least the use of a respirator. This is assuming of course that we are talking about the real deal as opposed to the "Bath tub" type.
One did notice that the hospital staff did not have any form of PPE when the causalities were admitted and I suspect that the 'rescuers' were in the same position re equipment. So why were there no reported casualties in the hospitals due to clothing contamination. This leads me to postulate that 'bath tub' Sarin was used which being unstable evaporated and degraded quickly.