I've got to agree... even in canon, Wilf told the Doctor not to save him, that he's lived long enough. If Wilf took matters into his own hands, the Doctor would feel guilty. If the Doctor did save him, he'd feel guilty and WIlf himself might get angry at him if he knew Ten could have saved Donna. Ten just always feels guilty, and it always seems that the Doctor is constantly put into no-win situations.

I'm wondering what would happen if Wilf explicitly told the Doctor to save Donna or Wilf's death would mean nothing, then Wilf pushed the button. Hmm...

I really, really wouldn't want to be in Ten's shoes!