Pearl's opponent was technically stronger than him. While he had the upper hand when it came to physical prowess, his enemy easily surpassed him with Qi. Even when his power was diminished when he used the White Tiger's Steps to split himself into two, his Qi would still be stronger than his, so he had to be careful.
Pearl had no intention of fighting two opponents at the same time when they were both stronger than him. So his only option was to defeat one as soon as he could.
There were really only two ways to defeat someone using the White Tiger's Steps that he could think of.
The first, and simplest, was to destroy one of the beasts, leaving the other to become the main body. That required Pearl to be strong enough to defeat the tiger, which he knew he wasn't.
