Why didn't Obi-Wan use The Force?

Question

While Qui-Gon and Darth Maul were having their final fight, Obi-Wan was simply watching them "trapped" behind a single shield/laser/plasma(?) panel.

So, at this point, why didn't he help out his master? He could have:

• pushed Maul to the hole;
• pulled Maul's lightsaber (or other kind of distractions);
• pushed his master away just before the lightsaber stab (after he got punched);
• melted the sides of that panel to rejoin the fight...

During those precious seconds, was he thinking it would be rude to interrupt his master or was he simply relaxing a bit?

Edit

It seems that some people comment-complaining and downvoting because they feel The Force is not to be used against "force-users", probably forgot how "force-users" use the force against other "force-users", here's the Obi-wan vs Anakin "kind of canceled force-push" in Episode III.

Answer 1

The only explanation for situations like this is going to be out-of-universe. This is because the way fictional fight scenes are constructed is governed by what audiences, primarily seeking entertainment and indoctrinated in conventional morality, will tolerate from their heroes.

1. Good guys (for the most part) don't fight dirty. They certainly don't fight dirty in the Star Wars franchise, where even an assassin can't be preemptively killed by a hero protagonist.

2. Ray Park. The entertainment value of the fight between Darth Maul and the two Jedi was the fight choreography that showcased the acrobatic and martial arts skills of Ray Park. Anything Obi-wan could have done whilst trapped between the force fields he could have also done earlier in the fight. Killing Darth Maul earlier doesn't allow the audience see as much of Mr. Park's extraordinary abilities. And such a death would have been less dramatically satisfying than Obi-Wan's sudden reversal at the end.

3. Telekinesis is visually boring. Contrast Count Dooku's dispatching of Obi-Wan by dropping a heavy object on him versus Anakin dispatching Dooku by chopping off both his hands and then contemptuously plucking Dooku's saber out of the air and using it to sever Dooku's head.

Answer 2

Using the Force could easily make things worse

First off, using the Force to push or pull things in combat is much more difficult than in a video game and could leave a target open for attack. Keep in mind that in this case, there was an ally right next to Darth Maul as well.

Second, Obi-Wan is still relatively untrained (only just ready to start the Jedi Trials) and doesn't have a lot of experience. Interfering with a fight between two people that each have twice the experience may not be effective (they may react to counter what you are trying to do), and could cause a distraction or other catastrophe that does more harm than good.

Knowing that using the Force to push or pull things in combat is very difficult, and that he has less experience than either combatant, let's consider the risks for each of your solutions:

pushed Maul to the hole

When Obi-Wan force-pushed the Battle Droids on the Trade Federation ship, very little precision was required: he was pushing a Battle Droid down a hallway with no allies in the way. This time, the two fighters are very close together.

It could very easily push Qui-Gon into the hole too, or cause Maul to move in an unexpected way, which might open up his master to an attack.

pulled Maul's lightsaber (or other kind of distractions);

When Obi-Wan force-pulled Qui-Gon's lightsaber, it was stationary and a few feet away, and even then it took a few seconds of wiggling before he could grab it. But doing this on a rapidly-moving lightsaber, held by two hands for much of the time, from farther away, and in a split-second window of time would be far more difficult. He could easily pull the wrong thing (maybe Qui-Gon's arm or saber) or just cause Maul's saber to move in an awkward way, again throwing off Qui-Gon.

There didn't seem to be anything else in the room to use (no giant pillars to throw around), so he couldn't have used anything else for a distraction.

pushed his master away just before the lightsaber stab (after he got punched)

He could just as easily have pushed Maul into Qui-Gon. And if he was successful, Qui-Gon would probably be off-balance, making it easier for Maul to get another good stab in.

melted the sides of that panel to rejoin the fight...

Assuming that it wouldn't cause a dangerous burst of energy if it were suddenly disrupted, this probably would have worked, and would not have been nearly as distracting to Qui-Gon as the other things suggested. I submit that in the heat of the moment, it just didn't occur to Obi-Wan to try this. He clearly had tunnel-vision, since he spent the entire scene looking at the fight, and not his surroundings.

Ultimately, most of the options that Obi-Wan had might have made things worse. The safest thing to do would be to not interfere and just stay put, letting his more experienced master buy time.

Answer 3

Because using the force on an opponent can always backfire and hit yourself

As we see in other occasions (e.g. in the fight Obi-Wan vs. Darth Vader, both flying away after an opposing force push) - using the force against an opponent leaves yourself open and can backfire. So if Obi-Wan tries to force-push the (apparently stronger) Darht Maul, his enemy might use the opportunity to deflect the push, or push Obi-Wan back. Obi-Wan was not really an experienced force user at this point. A deflection or counter-push will most likely push Obi-Wan back so strong he will fly back several feet.

But directly behind Obi-Wan is a strong energy-field, which spouted sparks when touched with a lightsaber. Similar looking energy fields have incinerated various objects touching them on other occasions. These fields are sometimes strong enough to melt blasters, so if a human would be thrown against them, he would most likely melt, or even evaporate.

Since Obi-Wan was in a tight spot between these two energy shields, one wrong push could have easily killed him instantly. So he had a much greater risk of being pushed himself. Darth Maul on the other hand was the better fighter and most likely stronger with the force, so if Obi-Wan would have tried a force push, Darth Maul could probably have deflected/force-pushed back and killed Obi-Wan easily. And even if Darth Maul would also fly aways from the push, even down into the hole, Darth Maul could have probably grabbed something or force-jumped of a wall and would not die.

So overall: High risk for suicide, little chance to kill Maul.