Prendick has a freak out moment—quite reasonable given the circumstances. He desperately tries to find a weapon and tears the side rail off a chair. A nail comes with the rail, so now he's got a makeshift nail-bat.
He hears a noise outside and flings open the door, catching Montgomery in the act of trying to lock him in. He swings the nail-bat at Montgomery but misses. Doesn't matter though because Prendick does what he does best. He runs.
Once in the forest, he stops and takes stock of his predicament. He's facing two vivisectors with guns and a forest full of beast creatures; not to mention he doesn't know the lay of the land or have any food or water. You've heard the expression, "up a creek without a paddle"? Well, Prendick's up the creek without even a boat at this point.
He decides that, if necessary, he'll walk into the ocean and commit suicide (not much of a strategist either).
He notices a black face watching him from the trees. It turns out to be an ape-like man. This creature comes down from the tree, having recognized Prendick from the boat.
The creature, whom Prendick soon refers to as Ape Man, takes a keen interest in counting Prendick's fingers. Prendick is already relieved—this fellow can talk. In beast society, human-like hands are especially valued since most of the beast people have deformed hands. Since Prendick is a natural human, he gets a free pass on this one.
Prendick asks for something to eat, and Ape Man beckons him to follow. He takes him to what he calls the "huts" located in a deep ravine.