Is it permissible to make the Adhan in the restrooms of metro stations if other station announcements are heard therein and it is impossible to stop them?

Hearing the Adhan inside the restroom is not problematic. If the loudspeakers inside the restrooms broadcast the Adhan, and they are primarily designated for broadcasting travel announcements, information, and emergencies, then there is no harm in this. This is because the restroom speakers cannot be separated from the general sound system due to the need for them in other announcements.