17:30 clear time without a 3rd person.
You fight exactly the same thing with 2 or 3 ppl for wave 2, so much better off doing it in a team of 3.
On lvl 80+ mode, wave 2 has insanely inflated HP opponents, but they do no dmg in return at all. Teams that are normally 1 shotted with ease by the fox did not even lose half hp. In return, normally strong attacks from the opponent like sage naruto mystery did only 200 dmg.