In this specific case you should be fine : after disembarking at 2F, follow the signs to the L gates. There is no security involved, just the Schengen exit check. Worst case is the someone turns you back (there are sometimes some airport staff checking BPs ahead ; then the PAF officer is unlikely to bother bus using the Parafe gates would avoid the risk).
At the end of the walkway there is a more or less hidden access to the L lounge (but anyway at this point you've technically already made your way to the L gates so the main access is not far away).
After this lounge session, you just need to backtrack the passenger flow from the main L security checkpoint, where there is an official egress - then the K gates are just a train ride away (the airside blue bus might also bring you there but not necessarily easy to find).

Btw, if challenged, there is a good reason to request access to the L gates : this is where the Yotel is located (access granted with a BP from 2E but not necessarily from L gates). Just saying...