Unless there is more going on, then no--the tenant would not have the right to break their lease and escape liability, based on what you write:1) First and foremost, a lease may be broken for only material, or important, violations, like unclean or unsafe conditions which the landlord won't remedy, or the landlord won't provide utilities or amenities which were in the lease. A rude employee does not even begin to rise to that level, whether it's your employee or not.2) Second, a tenant may generally only legally break a lease because of material breaches by the landlord or its staff, or if the landlord didn't cause the problem, it must be something making it essentially impossible to rent there. A rude employee again does not rise to anything like that level.