I used to work in an ammonia refrigeration plant, and can tell you firsthand that a capsule of ammonia isn't enough to present any danger, unless some of the liquid got in your eyes perhaps. Sure it'd be uncomfortable as hell, and could possibly have you gagging and crying, but the chances of any serious longterm respiratory damage from that small a quantity is very small.
One thing that's for certain is that when you are surrounded by several thousand tons of pressurized ammonia liquid you are forced to develop a respect for the substance.