Hi Vernon - having a military background is good -- i think the fact that you are used to discipline and can follow rule and procedures makes up a bit part of the job.
Yes -- you will have another interview -- the dreaded structured interview!! This is hard going..... but as long as you keep your cool (and you certainly should be able do that!) you'll be fine. Use the forum search to get more info on this - no point of re-hashing it here. One of the question though is "describe a time when you have had to deal with an emergency" I guess you'll have had an abundance of those!
Have a back-up scenario for each of your situations for your structured interview because it seems quite often they will ask you for "..... another time when you have ........ " ie saying the example you have given is not good enough so you have to give another one. This happen to me.
The reaction test is actually not too bad. You get a couple of practices first to get you into the feel of it. It does seem rather daunting at first as there are five coloured buttons, a LOW & HIGH buttons and 2 pedals to operate. I am used to the playtstation and Wii games so i didn't find this a problem. There's quite a good App (if you have an Andriod phone) called "Tap it" -- this is a take on the game "bop it" where you have different action to perform against the clock -- i found this quite good to sharpen up my reactions. The test speeds up twice as you go, but i still didn't find this difficult, i know a made the odd mistake, but here is the most important thing you cannot get flustered after you make a mistake - take a few seconds and pick it up again - again this is a test to see whether you can work under pressure. You repeat the test at your own pace after this, but again its a balance of going fast enough to pass, but not too fast where you start making a lot of mistakes.
So good luck with your interview - post back when you have the result -- i found them quite quick getting back to you.
Gary