Uh, no, it's not like that at all. Most of the deaths at the front of club were the result of crowd crush, which is generally the fault of poor crowd management and building design. When crowds start to get to the point of having 6+ people per square meter, the crowd as a whole actually begins acting like a fluid - the inwards pressure of the people all around you stop you from being able to act on your decision to travel one way or another, and instead you're basically carried with the motion of the crowd. If one person trips in the middle of a crowd like that, suddenly a space is opened up and the opposing force that had been present in that space, keeping the crowd in equilibrium, is gone - pressure is still coming from all other sides though due to the mass and proximity of people, so people bordering this new space generally trip and fall over the first person that fell in a kind of ripple effect (since they can't avoid the space, with the pressure of the crowd pushing them towards it), filling that empty space until equilibrium is reached again. Crowd crush is terrifying.
So basically, you had about 50 people pushing towards a bottlenecked front entrance (one hallway w/area ~7m2) with fire behind them and smoke blocking most of their vision, at crowd density of about 6-7 people/m2 - if one person trips and falls in that space, 4 or 5 more people are going to trip over that person, and now all of a sudden there's a block in this tiny hallway that can't really be seen by people behind it because of the smoke. As people come up to the block and realize they can't go through, there's still an incredible press from behind, causing them to fall on top of the people in front of them, stacking up a pile of living people 4 or 5 deep with pressure and fire still growing behind them.
It wasn't a matter of people who would "try to get over" the people in front of them - it's impossible to even try to climb up and over people in a crush like that.