Look to see what the piece of metal is.

I take one of them with me and continue.

You decide to keep going, and you almost make it, when the stones give way under you and you are plunged down the river.

Take the moss and keep going

I swim, or at least try to

As you go further, you hear the buzzing again, but much louder. It seems to be coming from behind you though. Double back or keep going forward?

As you bend down to get a better look at it, you see that actually just a piece is sticking out. Do you dig or leave it be?

You roll from the grating just as a stream of that stuff bursts out. You look around and see just one path.

You decide to not worry about the injuries now and go on up the mountain. You look up and see that you aren't making much progress, and you're tired. You see some sort of large plant ahead that could be used as a bed. Do you relax on it or go onwards?

You now have 1 bunch of moss

You swim, and though the current is rather strong, you manage to grab onto a large rock. As you climb onto it, you see that you are closer to the opposite bank. There is however, a foot or two of deep water still separating you from it.