Only 16 so bear with me here if i say something wrong...
The whole context of that episode and its other episodes are sabotaged and wrong, the lion wouldn't beat a tiger that has it in a grip, nor would a black bear beat an alligator nor would a gorilla kung-fu a leopard in midair nor would a brown bear survive the blows an Amur tiger inflicts....but regarding this topic, overall the right animal one because the Great White Shark is usually bigger and faster than the Saltwater Croc, however in context of what happened the Croc should have one, it savagely injured the shark by ripping its fin off meaning it wouldn't swim straight and then should have induced tonic immobility when it flipped the shark over...and once the shark loses its fin it should be scrambling for safety, it's not cowardice it's just that animal-safety impulse implemented within all creatures.
However i have NEVER seen a shark come ramming into an animal out of curiosity, it comes in full-force with its teeth unsheathed. Although in a normal and purely-fair battleground the shark would win because it's adapted better for underwater combat, these two creatures subsist on different climates of water firstly, wouldn't come directly attacking either and nor would the shark be so easily bitten apart and then somehow survive?
It's a good thing they didn't include the Orca in this, every beautiful and powerful animal in this got cheated, and I'd be feeling scandalous if the Orca got cheated.
I wish David Attenborough would come out and express something on this Animal Face-Off Show, he'd probably laugh and construe to them all how it's all utter bullshit.