Did Juliet cast the gas mask away at the end of the episode. Was this an indication that she was not doing Ben's will or not?

Its a sign she did. they probably staged Juliet's gassing to fool Jack/ Sayid/Kate.

I took that and the tying of the knot as a sign that she's still in cahoots with Ben.

Hm. Very good question. When I watch it again, I'll be sure to make note of how this all played out.

When watching it the first time, I thought she slid it down the table and caught it in her other hand. Hope that makes sense... Just a natural motion one might use to pick something up off of a slick surface.

That was what I thought initially but I'll definitely watch closer this time. ;)

My impression was that she just took it resignedly. Like, "If I have to do this I will, but I don't really like it."

She didn't toss away the mask or anything, she just picked it up.

The first time I watched it I wasn't sure, but on subsequent watching, she just picks it up weird.