Cory: We're not trapped with them, they're all trapped with me!

I like to think this helps explain later scenes, where he'll take pains to avoid cutting something he'd rather not with his swords.

Though I think that was from a filler episode.

Edit: I'm not saying the above scene is from filler, but that the later scene I am alluding to (but trying to avoid fully spoiling) is from a later stretch of filler a few Arcs from now.

No, this scenario should be canon.

They're referring to a scene in Alabasta that has a dung beetle rolling a ball of crap at a landship, and he takes other people's swords to cut it.

"No, GM destroyed and blocked off the escape route. I just saved you from negative HP."

Yeah pretty much

I think the DM was who she was talking to- ie the guy who ruled that the cut apart booger split just right to cause the collapse to trap them

3.5 do have some rules for damaging objects and also how caveins work. Granted he probably set up the area for something like this in the first place.