Some Assistance, Please?

Okay.

I've seen Jurassic Park at least a thousand times. Yes, that's pushing it, but I've see it A LOT. If it's on, I'll stop and take a look. I know it so well, that I don't need to see it from beginning to end; to get the gist of where I am in the story.

So here's my question.

Is there a very large error in the middle of the film? Am I the only one to have questioned this? Let's examine for a moment; the T-Rex attack. Arguably one of the most tense, exciting and scary scenes in the film. When I first saw it in the theatre (by myself; I might add), I was absolutely breathless when the scene completed. I mean, holy crap! Brilliant!

Anyway, so the two vehicles are facing the left of your screen; set up on their little "tour track". The goat is on even ground w/ them; just beyond the fence. The storm hits, the T-Rex; apparently also on even ground; just beyond that there fence...makes his way to ravage the kids, the attorney, the scientists and the poor Ford Explorers. Now, my issue here; is that once Grant and the kids go over the side; followed by the vehicle; and into the trees...there's a HUGE dropoff...just beyond the fence; say what; 20+ stories? The vehicles never move off of the "tour track" (okay, they move upside down); say to another side; where there might possibly be some large canyon...just beyond the fence...ON THE OPPOSITE SIDE. No. Did the T-Rex just climb up the side of the retaining wall? Was the goat sitting on some little island in the air; lifted up toward the heavens; from the deep canyon floor below?

I know I'm over-examining this; but I can't help but make note of it; every time I see it.

Anyone want to rationalize this for me? Finally, would the vehicles and their occupants have felt the T-Rex tremor so deeply; if it was 20 stories below?

I simply don't get this, and want someone to explain it to me.

Yes, yes...I know I'm a nerd, but I still want some answers.

That is all.