Doesn't matter whether someone hits ctl-c. If there was any kind of network interruption or your putty (ssh) session, then it can happen. If you were running the batch job as a cron task, or as a background job (nohup xxxxxxxxxx &) on the database server, then that would be a different story, but if you run the batch job remotely via a ssh session, then a problem with the network can cause the job interrupt.