should sb do sth

[joham]

They were told them that should the policeman tell them to go away, they were not to take him seriously.

Can the part in blue be replaced by 'if the policeman told/did tell them to go away'?

Could I ask native speakers to help me please? Thank you in advance.

[Soup]

Ex: If the policeman were to tell them to go away, then they should ...

Ex: If the policeman tells them to go away, then they should ...