[Sangetsu]

It can take several weeks for a COE to be processed. In my case it took about 5 weeks. Once you get your COE, it takes a couple days to get the work visa processed.

You cannot get an extension for a temporary visitor (tourist) visa. If your COE is not completed in time, you will have no choice but to leave the country, if you overstay your visa by so much as one day, you face the likely possibility of not being granted another visa for several years.

Running to Korea will probably work if you are from America, Canada, the UK, or Australia. If you are from the Philippines or some other part of Asia, they probably won't let you back in for at least a few months.