I don't know how the doors operate inside the Capitol building…
but if there are double doors (like the ones at the end of the hall where the lady got shot) the zip ties coud be used to zip the doors shut by putting a few of them on the handles/knobs. Or yes also for makeshift cuffs. But if you saw the double doors where the lady got shot, those were barricaded also to stop exit/entry.
So I would guess those zipties were for either capturing/taking hostages, or sealing exits/entries.
I'd bet those are the same brand/issue plate carriers. Even set up similarly.
Crazy to think that carrying out an op like that was easier than requesting info normally.
I understand they would object/block as much as they could for as long as they could… but damn, if it's that hard to get it must be very valuable.
People with Press cred who have been inside many times would have easier access and know exactly where to look. And if they are kinda nerdy/tech types with a Leatherman they would have no problem destroying/removing info.
Look at that dude… that's not muscle, that's speed. Not a weightlifter, more like a relay runner.