Malakai is an archaeologist.
He attempted to send himself back in time to see his deceased wife again, who died of a congenital heart weakness. Unfortunately, the machine created a time loop that encompassed fourteen planets, including Earth, P4X-639 and Alaris. Because Colonel Jack O'Neill and Teal'c were inside the field when it was activated, they were the only ones to have memories of previous loops, prompting them to learn Ancient to better understand the nature of the technology that they were dealing with so that they could take control of the console away from Malakai.
Although he tried to stop them by using a Goa'uld force shield, they were eventually able to convince Malakai to shut the device down after learning his reasons for trying to make the machine work, O'Neill using the example of the loss of his son to convince Malakai that it wasn't worth going to all this effort to see his wife again when all he would be able to do was watch her die. (SG1: "Window of Opportunity")