The longer you're in here, searching for the device, the greater the chance your captor returns for you. Also, since she let slip that other shrunken people exist, there must also be other machines that you could use. And finally, isn't this what you wanted? To attempt to survive on your own, in a giant world? Cutting loose without the safety nest of the machine will be great!
As the world settles down with the impact of the bag being put onto the ground, you flex your quarter-inch body and clamber up toward that gap in the zipper. Squeezing yourself through, you find yourself in a darkened world of noise.
To your left the great foot your captor throws you into shade, complete with its glittery pink nail polish. You back away from her, putting the purse between you as cover. From there, you can gaze out at toe level, seeing a narrowed view of the world. The feet of other people, from the restaurant meal earlier, are interspaced around the gargantuan room, moving back and forward in time with the booming beats echoing all around. Is that... music? Seems as if the birthday girl has a disco to end her special day, and to get out of here you're going to have to pass some dancing giants! Perfect, just perfect...
An impact ahead of you as the girl steps over her purse, her shoe smashing down and dragging the rest of her onward to the main dance floor. You are spellbound for a moment by such a gigantic creature, before shaking yourself out of it. Getting stunned by every single human you see will get you killed very quickly!
So, besides the deadly dancefloor - with the exit on the other side - a few people sit on chairs at the periphery, mainly those too old to be jumping around to the music. You could approach one of them to transport you out of here, or even work your way around the skirting board to get to the door. Of course, it would be quicker to cut through the dancers, and there's not much cover from roving eyes at the walls.
The giants have left their bags here, so you could rummage through some of them for any loots that might be of use in your new life. They are grouped near a 'small' table, but who knows what's on top of it. It could be a treasure trove, or it could be a complete waste of effort trying to get up there.