Jack likes his sonic blaster; it’s one of the best, from the weapons factories of Villengard, and it’s served him well for years. It’s especially useful for situations like the one he and his new acquaintances are in now, thanks to its ability to create nice, square holes in solid walls, just right for people to escape through.
Only trouble is, the second time he needs to use it he finds the Doctor has somehow switched it for a banana, which is a lot less useful. Fruit isn’t going to save them. Whatever the Doctor says, bananas aren’t THAT good!