Yes, that answer my question. I just believe that sending email via MSI is not very user friendly and wanted to use the standard SFDC email functionality which just takes ~3 clicks...
The contact is a duplicate, wrong process used. Instead of creating the lead, someone created a contact. Hence, we want to keep the right record (lead), but move any potential info...
Makes sense... Not exactly what I need, but makes sense. I guess I will need to remove the contact, instead of merging, but it is a shame that some info may just be lost completely...
Thank you both. I did review the documentation, but that field is just not there. I am thinking that maybe got created in Marketo first (?), and hence messing the mapping and all. ...