Eh, I don't think taking a -5 on attacks and granting combat advantage is worth simply being next to the goblin. Sure, I could get an OA if he tries to jump away, but it'll be nearly impossible for me to hit him thanks to the to-hit penalty. I'll just have to back up and jump across and then double move, then try to catch up on the next round. With the possible exception of finding out what in the next doorway, or around the next corner...
How far down is this pit?