It might help to start with what the Backplane Pathfinder actually is - it's a non-flight replica of the Webb telescope’s center backplane (that link has more info and pictures).

Chamber A allows simulating the cold environment the real telescope will face in space, and is the same vacuum chamber where Apollo spacecraft were tested.

Now, to answer your question: They are testing the test procedures for the real telescope! (source: NASA). I realise that doesn't exactly answer your question, but I haven't found details of the actual tests they plan to run... so as a distraction, here are some more images - http://jwst.nasa.gov/images_backplane.html

lucky760's reasoning is sound.

Anyone that has researched and/or trained on weapon on weapon defense, in this case knife vs. firearm knows the Tueller's Drill. It has been a standard for over thirty years. Basically,

The Tueller Drill is a self-defense training exercise to prepare against a short-range knife attack when armed only with a holstered handgun.
Sergeant Dennis Tueller, of the Salt Lake City, Utah Police Department wondered how quickly an attacker with a knife could cover 21 feet (6.4 m), so he timed volunteers as they raced to stab the target. He determined that it could be done in 1.5 seconds. These results were first published as an article in SWAT magazine in 1983 and in a police training video by the same title, "How Close is Too Close?"[1]
A defender with a gun has a dilemma. If he shoots too early, he risks being charged with murder. If he waits until the attacker is definitely within striking range so there is no question about motives, he risks injury and even death. The Tueller experiments quantified a "danger zone" where an attacker presented a clear threat.[2]
The Tueller Drill combines both parts of the original time trials by Tueller. There are several ways it can be conducted:[3]
The "attacker and shooter are positioned back-to-back. At the signal, the attacker sprints away from the shooter, and the shooter unholsters his gun and shoots at the target 21 feet (6.4 m) in front of him. The attacker stops as soon as the shot is fired. The shooter is successful only if his shot is good and if the runner did not cover 21 feet (6.4 m).
A more stressful arrangement is to have the attacker begin 21 feet (6.4 m) behind the shooter and run towards the shooter. The shooter is successful only if he was able take a good shot before he is tapped on the back by the attacker.
If the shooter is armed with only a training replica gun, a full-contact drill may be done with the attacker running towards the shooter. In this variation, the shooter should practice side-stepping the attacker while he is drawing the gun.
Mythbusters covered the drill in the 2012 episode "Duel Dilemmas". At 20 feet the gun wielder was able to shoot the charging knife attacker just as he reached the shooter. At shorter distances the knife wielder was always able to stab prior to being shot. (Wikipedia)

That a firearm, particularly a handgun, will instantly incapacitate an individual is not a working concept and is fallacious. Variables such as adrenaline and drugs are attributable. Shot placement is trumps. Anything but a CNS. central nervous system, shot is not efficacious in safely stopping the threat. Not an easy or sure target sans movement, stress, etc.

Law enforcement put their lives and safety in harm's way every day. They are not there to die needlessly. An individual with suicide by cop or a LEO's death in mind is a serious threat to be dealt with with prejudice.

By the way, research knife wounds vs. handgun wounds. There is much data, ER, medical examiner, law enforcement. The deadly seriousness of knife wounds are well documented.

Tasers...I would not want to risk my life behind one or anyone about whom I care.

Well... no, not really

But this one is road legal:

The nature of the game of experts and critiques schooled or otherwise in the realm of art, is that even if these are 'replicas' or forgeries that some smugly fart-sniffer will STILL spend bank on the gamble-I hope that's Banksy is disguise, say what you will about the artist, the guys' a genius guerrilla marketing enigma-

I freely admit being relatively ignorant when it comes to art, but even I would have recognised those as being Banksy pieces....and then I would have assumed that they were prints or replicas or whatever and kept walking.

This video has been declared a duplicate by the original submitter; transferring votes to the original video and killing this dupe - dupeof declared by braschlosan.

*dupeof=http://videosift.com/video/35-yrs-constructing-San-Francisco-replica-out-of-toothpicks

*dupeof=http://videosift.com/video/35-yrs-constructing-San-Francisco-replica-out-of-toothpicks

This video has been nominated as a duplicate of this video by deathcow. If this nomination is seconded with *isdupe, the video will be killed and its votes transferred to the original.

Oh I thought since I am not privileged it wouldnt allow those invocations

*dupeof=http://videosift.com/video/35-yrs-constructing-San-Francisco-replica-out-of-toothpicks

As the submitter, you can do that yourself and it doesn't need to be seconded.

Just do:

*dupeof=http://videosift.com/video/35-yrs-constructing-San-Francisco-replica-out-of-toothpicks

Crap. This is a dupe of an already sifted video from youtube. Can someone dupe it and instead add it as a backup to this - http://videosift.com/video/35-yrs-constructing-San-Francisco-replica-out-of-toothpicks

How about the biggest convenient but totally improbably plot point miss in all of Avatar: They have such incredibly advanced biological technology that they can grow (nearly) exact replicas of an alien race with enough advanced hardware in their heads to allow them to be able to remotely control them and yet they can't FIX JAKE'S SPINE. (:

Actually it's even more bizarre. As radx mentioned it wasn't a gun, but a gas pistol; a replica which can only fire tear gas rounds or blanks.

Blanks can be fatal at very close range, but it's far from a sure thing. I can't really guess what he was trying to accomplish. Possibly just crazy and inept.

http://en.wikipedia.org/wiki/Gas_pistol

http://www.chron.com/news/world/article/Gas-pistol-pointed-at-Bulgaria-party-leader-4207697.php

I'm really not sure why everyone is making such a big deal out of it. They didn't have the rockets for it, just the launcher.

Everyone comes here and posts videos about how the police abuse the system and how inept they are. Then we are willing to believe the police aren't just holding a replica and are too dumb to notice?

Someone out there probably paid like $300 for "Military Replica Style Rocket Launcher" and sold it to the cops for like $2,000 and he's laughing his ass all the way to the bank.

Otherwise wouldn't we hear "Bizzare Rocket Launcher Murder solved!" No questions or not I can't believe they would just let that guy go.