You're welcome and I wish you the very best in your nursing career.
As a retired nurse who has been splashed with a great many unthinkable substances, your supervisors/superiors were correct that you had nothing to worry about.......but, in my humble opinion, they were unkind and unprofessional to laugh. You had a very legitimate concern and they blew a great teaching opportunity. Shame on them.
(Hang in there.........being a student nurse is like being in the 4th circle of hell)