What year does Half-Life 2 take place in

If I remember correctly you need to get out on the middle span and get it to tilt down towards this span, like a seesaw - it's got a bunch of heavy crap tilting it the other way that can be knocked off with the gravity gun.

It's been a few years, though. That might be total malarkey.

You can't dismiss them to my knowledge, but if they're obstructing your path, you can toss the bugbait behind you to direct them elsewhere.

I also seem to remember that if you press hard enough through them, they'll budge out of your way like any other NPC. In any case, it's usually best if you direct them forward as much as possible to soak up enemy bullets.