Let's think about this deal Marty got. He could...
1. Use the idol at tribal thus keeping himself in the game another 3 days while Jill goes home
2. Give the idol to Sash, basically his enemy in this game, which will keep him in the game another 3 days while Jill goes home, but also potentially giving Sash and Co. the ability to vote him out. Sash did promise to return the idol, but that ain't happening.
Really bad strategic move by Marty. The only way he can get it to work to his advantage is to convince Brenda or Fabio to ask Sash if they could hold it. I am pretty sure Sash isn't going to give it up, and this would cause some friction with the younger players and might keep him in the game a bit longer.
I loved Jane keeping the fish for herself, I know I would have done the same thing. Heck, I would have eaten all three and told the lazy POS kids I didn't catch anything.