As before, Daniel had not accompanied the other wise men whom the king had summoned (cf. Daniel 4:6-8). The reason for this is unclear, but the effect in the event and in the narrative is that it sets Daniel off as unique. Clearly Belshazzar did not know Daniel personally. Perhaps Daniel had left public service by this time. [source][source][source]
When really severe crises arise, it is often the man or woman of God that others turn to for answers. [source][source][source]