Stealth classes can just sneak to the area and use the tablet, no need to kill him. Note it's not a "pick up" type quest where it takes a few seconds to use it and get the next part, rather you just click the tablet, click a little thing to get to the next page of the text and you're done, so while the guy patrols around the other side of the square-type route he takes it's easily doable.

Theka the Martyr patrols a large room in the western part of Zul'Farrak. The room is full of scarabs, but they are neutral beasts. Just be sure to avoid using AOE attacks and they'll leave you alone.

Theka himself is fairly easy to start. Just blow him away like you would any other mob. However, when he gets to about 30% health, he will become immune to all physical damage and all Shadow magic. This means that you need to have a mage, priest, druid or shaman in your party (or a warlock willing to use only fire spells). I believe paladins can also use damaging judgements. I originally tried this quest with a party consisting of hunter, rogue, paladin and two warriors. Beating Theka was not easy with that group :). If you have a mage, it might be a good idea for them to not pour on DPS until Theka hits 30%.

Once you've killed him, you can read the tablet in the middle of the scarab room. It's leaning against one corner of the crumbling structure there.

Confirm soloed by a level 45 Hunter! I was a little nervous that I wouldn't be able to pull it off, but here's my advice for Hunters to do it as well...

Bring plenty of your pet's favorite food type, at level 45-level. That's the only thing you need to bring beforehand -- no special/invisibility potions.

Put on Track Humanoid and make sure you're handy at firing off Feign Death. Also, go into Aspect of the Cheetah (not Pack, you'll want to make sure your pet is able to run as far as it can).

It also helps if your pet has Dash or Dive trained, so it can move quickly.

What you'll want to do is run as far as you can with your pet running ahead, aggroing as many groups as possible before it dies and the mobs turn it's attention to you... then Feign Death in a 'safe spot'. There are many places in the grounds of Zul'Farrak where you can stand still and be safe from patrols so you can rez/heal/feed your pet between these pulls. I know many of them because of having run the instance many times before on my other alts -- I might come back here and mark a few places on a map where I Feigned Death and recovered. I will note, though, that the first main hallway where there are Shadowcasters channeling against the wall, there will always be a few patrols going up and down the way... but there'll be a good 1-2 minute break where you can stand safely against the left wall where you can prepare for your next charge.

The most challenging area to get past is the area where you can go either left or right (go right to Theka the Martyr's room), but I can garantee you that as soon as you clear that area, you've pretty much won the war. Also, to the right of that room is a nice big, clear area where you can heal up your pet. The "hall" leading up to Theka has only two patrols, and I had no problem sending my Raptor up to aggro one, then run up to snag the other as I ran on past them, and Feigned in the corner of the giant Scarab room.

When you get there, you don't even need to kill Theka. Simply run up and stand in the center and read the tablet. Hearth and you're done!