Bio-Effects of Radiation On Planet Mercury

I am trying to establish whether humans could ever explore Mercury's surface during daylight periods. Essentially, the issue is how long the crews could be directly exposed to solar radiations before absorbing excessive (cancer-causing) doses of radiation.

Solar heat is always noted as a principle threat to humans should they ever go to the surface of Mercury. However, after sunrise, it takes several weeks for the surface temperature to rise to the boiling point of water, set here as an arbitrary limit for crew safety. This suggests crews could have sufficient time to perform surface exploration before temperatures exceed safety limits.

The issue here concerns particle radiations. Particle flux at Mercury would be expected to range between 6 and 10 times the flux at 1au. NASA requirements for astronaut exposure limit dosage to 50 Sieverts per year. Not having a background in physics, I am not clear on how to translate the flux rate to a dosage figure.

Does the flux rate noted automatically preclude human excursions?

An important secondary question is what would be suggested for sufficient radiation shielding (thickness) for habitats if regolith were used?