There's no good idea. First you must understand something.
1- Session by default is 30 minutes
2- Session are not lost meanwhile user make some operation, to ensure while openkm is enabled user don't loses session, there's a background method in UI that each 15 minutes makes a call to server to prevent losing session ( scenario -> users has left for more than 30 minutes his job computer, with OpenKM screen openend or simply has closed the window while is doing something in other ... he's not making operations and could lose session to prevent it we've got this background method fired automatically each 15 minutes ).
What could happen
1- You could configure for less than 15 minutes ( if you understand what I said before you must understand the problems that you'll got changing it ).
2- To better configuration it might be changed the method period ( by source code ) to the new .. really having 1-2 minutes that you purpose it not good idea, if you understand the idea of session ...
I think your problem is bad users logout no ? in version 5.0 we're working to correct the one session per user, that will solve the problem, users can start other session meanwhile the other is still alive ( meanwhile you could use administrative utilities to kill user session ? )
In wiki you've got explained how to reduce session time out
http://wiki.openkm.com/index.php/Changi ... ut_session