By enabling the option "Include From, To and CC when evaluating which emails will be processed." (in Advanced Options for Step 2), the headers and not the envelopes takes precedence over the actual Sender/Recipient. In other words, gets the initial RCPT TO line and connects to the destination mail server.
 

• Headers From, To and CC. are present in email sent to all the recipients in the envelopes.
• Envelopes (Sender and Recipient passed trough email servers) are not headers, just part of the SMTP protocol, this is per each combination of Sender/Recipient

Notice when using an exclusion in a rule with this headers enabled, the exclusion is calculated with the headers present on the email and not by the actual Envelope (Sender/Recipient) information from the SMTP protocol.