Clarifying Sequencer's Role in Outbound Email Comms

A client of mine is considering using sequencer for outbound emails. In additoin to receiving email replies emails from prospective customers, they also receive inbound emails from current customers with sensitive patient data. They don't want this information to flow into Clay. To the best of my knowledge, Sequencer will only be responsible for outbound comms, and therefore no un-wanted inbound/replies would be flowing into Sequencer. Is this correct?