If they are willing to bomb the plane they are ridding then I don't think they are going to care about long term damage from drinking it. So worst case you eat something to slow the poison and then blow up to plain in an hour or so. Which brings up a separate but important point, you could probably smuggle a lot of explosive the way they move heroin. The blast would be muffled by the human body but... nm.
Actually the human body is quite good at muffling explosions and would require a substantial amount of explosives to cause large damage outside of ones body.
