Is it permissible for a worshipper in an office to follow the congregation of the mosque located beneath the building, knowing that the mosque does not have a designated area for women?

If you are unable to hear the takbir and see the Imam or the congregants, your following this congregation is not valid, as some scholars stipulate this, and the first opinion is the more cautious one. The presence of a colleague with you in the room does not affect your prayer. You must inform her that it is not permissible to delay the prayer beyond its appointed time, because prayer has a specific time that cannot be advanced or delayed except in certain circumstances.