There's a rotten egg in there. Remove the hen to a box or other closed container, inspect the eggs and if any are cracked or discolored, remove them. Sometimes eggs die, even an entire clutch can die, and the hen may not necessarily realize this. A healthy egg will look like a normal egg, a rotten egg is sometimes greasy looking, or may have tiny mites crawling on it.
If the bedding material is dirty, wrap the remaining eggs in a cloth to keep them warm and change the bedding quickly, then replace the eggs and the hen. If she's as angry as you say, she will probably sit right back down on them.
I concur with Tyler. Rotten eggs are no joke and will only get worse if left alone.
If you have to do anything with a broody hen (or any chicken really) the best time to do it is after dark. They tend to be pretty catatonic then and it's much easier to move them around. Broodies will still be a bit irritable but it's much more manageable.
It would also be a good idea to candle the remaining eggs to see if they are viable. Once one egg goes rotten, it tends to spread quickly to the other eggs. If you can remove any of the eggs that are clear or obviously dead (no veins, large red or greenish blotches freely sloshing around, red ring), it will reduce the chance of more of them going bad.