stuck in chapter 3 or 4?

[steelth1]

i,m at the part where you walk into a large open round area an he says " summit meeting heh" then one of those big guys with a hammer comes in and then the ground collapses and you fall into another large room and fight this guy. ok, so i killed him and picked up all the dinomite i can carry. now what? i tried using the dinomite on the hole in the wall blocked by metal but nothin happens, i walked down the hallway with the high ceiling but it's a dead end. can somone help me? i played this game once about a year ago and hated it but i gave it another chance and found out it.s a lot of fun once you learn the moves and controls. thanx.