I think i have partial answer to this problem
Partial as it worked for some videos and didnt work for some.I am still trying to find the cause.
I dont think it is very secret technique,what i do is
Start recording using
Replay Media Catcher
start the video
and then click on the desired time in timeline
the another file starts recording
and delete or stop the original recording in media catcher
but for such middle part captured videos...
some are normal but most have audio only(vlc) and classic media player says codec error(i think this may be solved)
so,this is what i do ....
may be u can give a try