No. You cannot copy the code of total commander, but you can create split file manager using your own code. There are split screen file managers available with other OSes. For example, there is vifm, midnight commander, gnome commander in linux and ghost commander in android. I don't know or care if there are similar file managers in mac or windows.
EDIT: As google would like to add there are plenty split screen file managers available in both windows and linux ( I have only tried those I mentioned above)