Knowing full well that the Boss Zombie would be ridiculously stronger than the Spear and Sword Champion, Pati deliberates his choices while still sitting on the ground. On one side he wants to play it safe and come back later. But on another side, he wanted to finish this Dimensional Portal Quest in one try.
From what Havel said way back, the Dimensional Portal has been entered 3 times.
Although Pati doesn't know whether using the Escape Item to leave will affect the Dimensional Portal Quest or even the Zombies inside, there's a chance that it would go wrongly and he didn't want that to happen.
With the survivors from the other safe havens scouting him, it's clear that he needs to get stronger.
