Canyons are inherently risky. Flash floods occur without notice on sunny days. Technical skills & surrounding topography knowledge required yet does not eliminate risk.
Canyon X may be one of the least visited slot canyons open to the public. Generally only between 4-6 people are allowed into the canyon per day, and only one company is allowed to bring people into the canyon. No private hiking of Canyon X or Cardiac Canyon is allowed at this time.
After being driven out to the trailhead by your guide, near the upper end of Canyon X, you begin the hike. The first portion of the hike is the most exposed as you cross the bench between X and Cardiac. The tours run down Cardiac and up X because the entrance into Cardiac would be a serious pain to use as an exit.
After a couple miles along the bench, the trail drops down into Cardiac via a short side canyon almost entirely filled with a giant sand slide. This steep entrance is part of the reasoning for the name 'Cardiac'. After sand-sliding down the slope to the bottom of Cardiac, most guides will take you upcanyon for about a quarter mile to the base of waterfall/plunge pool. This route is not for the large, unathletic, or generally out of shape as some serious scrambling and contorting, as well as chimneying up to ledges. The rewards are worth it, however. The narrow, convoluted walls are magic in the morning light, and the vertical waterfall face is amazing. Not a place to be stuck during a flash flood, but when it is dry it is a sight to behold.
Returning downcanyon back to your entrance point into the canyon, the group should regather and begin heading down again. The canyon slots and opens on and off throughout the descent of the canyon. During dry spells walking in the wash bottom can be quite taxing, while after an overnight rain the going can be somewhat easy. Great Horned Owls are often seen in this section of the canyon, and Mountain Lion and Bobcat cats are commonly sighted too. The slots and open areas alternate more as you continue down towards the mouth of X, with broad open areas beginning to predominate.
At the mouth of X, your guide will turn right and head upcanyon. At first it appears the canyon dead ends, but then suddenly turns to the right. After traversing a broad, shadeless area of canyon bottom, the canyon slots up yet again. This section is the most spectacular stretch of all the Cardiac/X system, with deep, tight twists and a natural bridge. It doesn't last for long, but it is amazing.
Exiting this stretch of slots, you cross another short area of open wash bottom, and then enter the last, upper section of slot that also, like Cardiac, dead-ends at an enormous pourover. After oohing and aahing, the guide will lead the group up a much more manageable sand hill to the rim of the canyon, then along a fenceline back to the guide's vehicle.
While at the time of writing there are no unguided hikes available to the public, and the tour company providing tours will cancel or cut short any tour if there is any chance of thunderstorms or flash floods, it is worth re-mentioning that slot canyons should not be entered when there is a good chance of rain or flash floods.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.