The 5th amendment gives people the right to refuse to testify, as a witness, in a way that might incriminate oneself. Relatedly, it excludes self-incriminating statements in certain circumstances from evidence in criminal cases. While the 5th amendment has been interpreted to apply to many different proceedings (not just criminal cases, as in the text of the amendment), there must be some sort of proceeding of a disciplinary nature.
If the survey results were not shared with the police or intended to be used in a criminal case, it's quite likely not the case that the 5th amendment was implicated at all.