A method includes deploying a downhole tool within a wellbore. While the downhole tool is within the wellbore, the method also includes slotting or perforating a casing of the wellbore at the target interval to expose formation surrounding the wellbore. Further, the method includes flushing the target interval to remove wellbore debris from the target interval. Furthermore, the method includes pacing a cement or sealant plug at the target interval.