Your account and your organisation
Two sets of settings, in two places, and the difference matters.
Yours
Your profile, your password and security, your active sessions, and which notifications you receive.
These follow you. If you belong to three organisations, you have one account, one password and one set of notification preferences across all of them. Changing your password does not change anything about any organisation.
The organisation's
Members, invitations, teams, roles, billing, the audit log, feature toggles and organisation settings.
These affect everyone in that organisation, and they need organisation-admin access. If you belong to three organisations, each has its own set and being an admin in one grants nothing in another.
The one that sits across the line
API keys are managed under your own settings, but they authorise access on behalf of the organisation.
This is the exception worth knowing about. The screen sits with your personal settings, so it is natural to read a key as yours — something scoped to you, with your access. It is not. A key acts for the organisation.
Anyone assuming otherwise will underestimate what a leaked or over-shared key can reach. See create an API key.
Sessions are genuinely yours
Your active sessions are the devices and browsers signed in as you. Ending one signs that device out.
They are not an administrative tool: you cannot see or end another member's sessions from here. Removing someone's access to an organisation is a membership change.
Notifications are yours, and per person
What you are notified about is your preference. Two admins in the same organisation can be notified about entirely different things, and neither setting affects the other.
So "nobody was told" usually means nobody had that notification switched on, rather than that the organisation was misconfigured.
Leaving an organisation
Your account survives. You keep your profile, your other memberships and your sessions; you lose access to that organisation's data.