Lounges in PEK: Console yourself that you aren't missing much. And do write that report.

If you get to Tiananmen early enough, you might be able to get into the gate with Mao's picture on it into the large forecourt, which has lots of vendors around, and you can walk as far as the Forbidden City entrance but I think will be too late to go in anymore. But if you get that far, to your right will be another set of gates that you can wander out of and get a good view of the moat and some pics. A fast walker could exit that way, walking eastbound, toward Wangfujing street (have a map of the streets of this area with you) and the famous night food market with the crispy critters ready for snacking. Side order of crunchy grasshoppers or scorpions for ya? Then turn down Wangfujing pedestrian street area and walk back to the subway Line 1 for return trip. These areas will be bustling with people and quite lively early on a summer evening. Hopefully it won't be pouring rain!

If the gates under Mao portrait are no longer open when you get there, enjoy the square quickly, then about face down the main sidewalk east to the first street with a light, turn left and walk north until you see a bunch of activity coming out of gates on your left, that'll be the eastern gate/moat area, pick up walk as above from there. Note: it is not a short walk so be wearing good walking shoes. Beijing city blocks are much larger than maps imply.

One of the more interesting things about the Mao sign is watching the locals (usually non-Beijingers) staring reverently (or not) and pointing and generally reacting to being there. Not sure if the Hollywood sign provokes quite the same response, but an interesting analogy.

If Mabuk gets lucky with his timing, he might be able to hit Tiananmen just when the soldier's Honor Guard is doing the daily flag-lowering at end of the afternoon. There will be some small crowds around for that.