consternation

Consternation is dismay at something unexpected. Not fear exactly — the confusion of a plan coming apart.

It is a formal word and it usually describes a group, so consternation among the staff and to the consternation of the organisers are both standard. Much to the consternation of is close to a fixed phrase. It carries a faint note of comedy, since it is often used about people upset by something fairly small, and writers exploit that. The verb consternate exists and nobody uses it.