Does anyone know a console command to kill all scientists on the map or only on the oil rig instantly?

There's no command

You can delete all of a certain prefab with del <prefab>. So if you wanted to destroy all large furnaces you would do del assets/prefabs/deployable/furnace.large/furnace.large.prefab in the console.

Edit: this will destroy all of the prefab and can't be reverted so be careful when using it.