[parappa]

Perhaps, but couldn't button also have 2-pair? I don't think it's particularly important that there's now a 4-straight on the board; if he's got a straight, he's supposed to already have the 6. We have a lot of outs against something like 87 (4 5s for a chop, 3 4's, 3 6's and 2 J's for a win). I'm thinking it might be a call as played, though I think I would've bet/folded the turn.

Edit: my outs calculation was a mess. I took another shot.