I don't think you are breaching any clause.
As per Salesforce docs:
We STRONGLY advise against this practice! Salesforce cannot prevent
individuals from sharing their login information or from allowing the
practice of having many Users login via the same User record, but
there are many reasons why no one should adopt this practice.
By using the same username with different users you will run into
internal org issues. Security between accounts, contacts, or other
objects is no longer considered, data integrity will be an issue and
auditing will prove to be hard to do. The user will have no way to
track any changes done within the org since there will be no
differentiating on what has been done from one person to another. The
Setup Audit Trail is rendered useless in this scenario.
If multiple Users are logging in via the same User record, there is no
way to track which one of those individuals modified, created or
DELETED something in Salesforce. This can wreak havoc on an Org.
Yes, it's technically possible, but please do not do it.
Multiple Users log in with one User record