I don't know if they arrived separately or together. The DOD news agency says that when they did, Hasan fired on them. They ducked behind a car. Hasan then went out of sight around a building. The officers, following active shooter protocol, pursued to engage. As Todd recalls, their training took over perfectly; they were working as a team, coordinating, yelling commands back and forth. Munley pursued Hasan directly. Todd went around the other side of the building to engage from that side. From this point, unsurprisingly, their accounts differ.
Here's (a secondhand version of) Munley's recollection: she went around the corner after Hasan. They exchanged fire. Munley went down. Hasan moved toward her, still firing. Munley continued to fire. Hasan was struck in the upper chest and dropped.
That's how (we're told) she saw it. Here's how Todd recalls it: Todd came around the corner and saw that Munley was down and Hasan had turned his attention from her to fire at people who were running away, trying to find cover. Todd yelled that he was a police officer and told Hasan to drop his gun. Hasan turned and opened fire at Todd, but none of the bullets hit. Todd recalls firing five times. Hasan went down, and Todd jumped on him to confiscate the gun and cuff him. He realized people were shouting, "Two more! Two more!" at him, and thought they were warning him of two more shooters before he realized they wanted him to give Hasan a double-tap -- i.e., shoot Hasan two more times.
Reporters trying to reconcile their accounts asked Todd if he'd seen Munley shooting on the ground, and Todd said as soon as Hasan opened fire on him Munley dropped completely off his radar screen and he had no recollection of her at all. That's classic gunfight tunnelling: she could have put on a gorilla suit and danced the hokey-pokey, and Todd wouldn't have noticed; you'll doubtless have noted that Munley, who'd already engaged in close-up gunfighting and been seriously wounded in it, was tunnelling herself because she *didn't even see Todd was there.* My bet is that they were both shooting at the end, and that Munley fired at Hasan from the ground but was mistaken about his direction of movement, but it'll be a while before the FBI is done with their reconstruction. Regardless of which of them fired the shot that took him down, both of them are Officers of the Year, and they officially have balls of steel.
(I don't know about Todd's family, but Munley is married with kids; her husband is in special forces and she's a SWAT team member and firearms instructor who doesn't shrink from rushing an armed mass murderer, so I guess their kids are going to grow up to be every eighties action hero ever.)
Here's what I know on hardware. News organizations have reported that the perpetrator carried a "5.7-caliber gun," meaning the FN Five-seveN, in 5.7mm, and an older-model Smith & Wesson .357 Magnum. (The NEW YORK POST mentions that 1) Todd's gun is a Beretta, which means probably a 9mm Beretta 92FS or similar model. I figure Munley carried the same; that's the gun Todd would have carried in the Army, so he was familiar with it from two careers. 2) the perpetrator's gun had a laser sight.) The perp bought the Five-seveN legally from a local gun store; no word on the Smith, which may not have been fired at all. (Though if it was, that would be one reason there were reports of multiple shooters; the guns would have sounded quite different.)
The Five-seveN can use magazines of 10, 20, or 30 rounds; it can defeat bulletproof vests if you have the appropriate ammo, which one of the most all-around knowledgeable gun nuts/sellers I've ever run across says is kept locked up by the manufacturer and only released as orders from police or military institutions come in. (I don't think the perp, despite being military, could have acquired it on his own, and the reports now out there are that he just used standard civilian ammo.) Eyewitness reports state that, like the VA Tech shooter, he shot people multiple times after they were down. This is why I always say that playing dead is not a great tactic. OTOH, one of those eyewitness reports came from a guy who successfully played dead, so it can work if you're lucky.
The shooter, Major Nidal Malik Hasan, is an Islamist fanatic. Some media outlets, particularly Time and Newsweek, are pushing the traumatic stress theory -- he heard terrible stuff from his patients with PTSD, and had been harassed for being Muslim, et cetera. I think emotional imbalance was a component, but I think TIME and NEWSWEEK are focusing on it way too much. (The Orlando shooting, committed by Jason Rodriguez, in which mercifully only one person died, is a really classic emotional imbalance workplace shooting, though the long delay between the instigating incident and the concluding is curious.) Hasan had been on his current gig only briefly, and in any event neither newsweekly was inclined to be half so understanding of the personal hardships of any other mass shooters, which was proper because they bloody well shouldn't have been. It seems to me they're hammering Hasan's personal troubles because they don't want to grapple with the fact that Nidal Hasan was a religious fanatic.
There are reports that intelligence agencies had Hasan on their radar, and that he might have reached out to Al Qaeda types online. If that's accurate, whoever was in charge of his case should be fired. I have no idea whether he will turn out to have been acting on orders, or if he was a case of what's been called "sudden jihad syndrome." There are a lot of alarming things that are coming out about his religious hang-outs: his former imam, who's been giving interviews about how shocked he is that Hasan killed people, is on the board of directors of the Islamic Society of North America, which is an offshoot of the Muslim Brotherhood and was an unindicted co-conspirator in the Holy Land Foundation case. Not warm and fuzzy guys. Two of the 9/11 hijackers went to Hasan's mosque, and one of their former imams -- whom Hasan heard preach -- once glowingly described by the New York Times as a modern Muslim leader who bridged the old and new, has fled to Yemen, where he operates as a pro-jihad propagandist and has apparently dabbled in shuffling arms to Islamist groups. He posted to his website praising Hasan's actions. The BBC correspondent doing interviews at Hasan's mosque found a young guy named Duane who gave Hasan's actions a serious, sober, thumbs-up.
I think the odds are still pretty good that Hasan acted alone, but whether he did or not this is looking more and more clearly like a jihadist attack. Hasan would not be alone as an unsupported jihadist, BTW; sniper John Mohammed (Washington, DC area, 2002), mass shooters Naveed Afzal Haq (Seattle, 2006) and Hesham Hedayet (Los Angeles, 2002), and attempted-mass-murderer-by-automobile Mohammed Taheri-azar (Chapel Hill, NC, 2006) were all similar cases, so while it's not impossible that Hasan took orders from somebody it's quite probable that he planned and executed everything himself.
A final note: restrictions on arms at Fort Hood meant that Hasan, who smuggled his own guns and ammo onto the base for his rampage, had a target pool full of people who couldn't fight back. This is a policy by the army to cut down on drunken accidents and the like; as I've mentioned a few times before, these policies don't seem wise to me.