I worked at a hospital about 10 years ago, and at that time only IE was available on our PC. PC workstation was locked down for security reason and users were not allowed to install 3rd party software without approval (including chrome, etc). Also Chrome's browser extensions were security concerns (esp for medical records, HIPPA regulations, etc) It was also a time when IE was used in enterprise for mostly legacy web app that was written long ago. We were also using command line apps (TUI-based) at that time, mostly for nurse and doctors, but we were migrating to the fancy web apps.

As for Korea, IE was mostly for ActiveX, but now most Korean website supports modern browsers ie Chrome.