I'm unable to leave Ching's apartment after having accomplished all that is to be done there. I've checked with walkthroughs and I;ve done it all, but can't get out. Can't get through the hole I cut in the window, and the exits are blocked by security gaurds. Any help?

Is there something in the hints menu regarding Ching's apartment?
I ask because you can only "purchase" hints for stuff the game thinks you did not do yet, so it would be a good idea to take a look to figure out if something was not triggered right.
I can't remember off the top of my head if there was something special you had to do to leave the apartment. You did try the travel menu, did you?

Yikes, I'm so embarrassed! I was thinking I'd automatically find myself back in the office - forgot all about the Travel option. Thanks, and sorry.

I think I made the same mistake when I played through UAKM a few years ago, wandered around aimlessly for half an hour, and then felt really stupid when I used the travel option. After carefully sifting through fo god knows how many walkthroughs trying to find the answer and not spoil future events for me in the process.