Do you mean unintentionally?
It's very unlikely. Anatomical knowledge developed in tandem with embalming techniques, and Egyptian medicine was really quite well developed all things considered. Most physicians were probably fairly good at recognizing signs of death. At the very least, Egyptian physicians distinguished between conditions which could be treated and those which required more of a battle. The Smith Papyrus includes a third category of illness, those which can not be cured and which a physician should refuse to treat.
As I am not a medical expert, I can only guess at some reasons why an ancient Egyptian might take on a death-like appearance. Some illnesses are known to result in coma, And it's possible that some kind of spinal or brain injury might result in this. Egyptian physicians evidently had reasonable detailed knowledge about all of these conditions. For example, the Edwin Smith Papyrus, has remarkably detailed diagnoses and descriptions of spinal and skull injuries. It discusses, among other topics, the causality between vertebral injuries and stupor or aphasia, as well as the loss of awareness in certain limbs or parts of the body. This means that physicians might be expected to have some level of familiarity with neurological damage. Unfortunately they also offer a bleak prognosis for some of these injuries, implying that they were not easily treated.
Plants and concoctions which had sleep-inducing or narcotic effects are less well attested to. It is generally held that opium was not used widely in Egyptian medicine until the Ptolemaic period brought a significant Greek influence. This makes it unlikely that someone would fall unconscious due to narcotics. Without knowing more about the underlying condition, it is hard to speculate on how well an ancient physician might have dealt with it. The precise magical and medical beliefs that informed your physician's prognosis might have varied considerably, so I can make no promises about their accuracy. Any diagnoses made were based in large part on empirical evidence borne out of their personal experience, rather than a more standardized scientific approach.
Instances of accidental live burial which occurred during the early modern period have fuelled some more macabre imaginations in recent years, and I suppose similar errors could have been made in antiquity. Let's say that for whatever reason, you are sent to the embalmers because of an error. The embalming process begins with washing the body. It seems likely that signs of life might be detected during this stage in the event that you were mistakenly pronounced dead. Embalming priests were fairly familiar with anatomy, given the obvious overlap with mummification. Hopefully the embalming priest who tended to your body would have good observational skills.
If your loved ones could not afford a thorough embalming, they might settle for simply having your body washed or scoured with sand, and then packed in natron, or even cheaper, regular salt. However, for the sake of this question let's assume they went all out. The whole process would take about 70 days total, 40 of which would just be spent drying out your body. According to Herodotus, the bodies of beautiful and upper class women were withheld from the embalmers for 3-4 days, to protect them from unscrupulous embalmers. This is really spurious and most historians and egyptologists doubt that this was ever a practice. However, precisely how soon you got to the embalmer might have depended on other, more practical factors. The length of the embalming period also varied (Meresankh III was not buried until 272 days after her death!) The idea of someone not being freshly dead by the time they were embalmed is definitely not far-fetched.
If you were somehow still alive by the time they started embalming, you wouldn't be for very long. To prevent putrefaction, embalmers immediately began removing the organs before they had a chance to break down. Hooked instruments were inserted up through the nostril and used to pull out the brains. The removal of the brain would obviously be immediately fatal.
An incision would be made in your side so that the embalmer could pull out all of the organs and viscera inside your torso. Your entire chest cavity would be emptied, leaving only your heart which would be pushed up into a slightly different position. An alternate method of organ removal is attested to by mummies from Middle Kingdom Thebes. These mummies were given an oleoresin (possibly turpentine or juniper oil) enema, to liquify their organs so they could be pulled out through the rectum.
Assuming you lived after around the 9th Dynasty or so, they would start preserving your body. That involved packing your body in natron and aromatics, and shoving it into your body cavities. This would soak up moisture and prevent foul odors. The natron would be changed out regularly as it soaked up moisture. Your organs might also be preserved in jars, soaking in a mixture of beeswax, resins and oils. After the 21st Dynasty or so, they might be preserved and wrapped before placing them back inside your body.
Some mummies had false eyes, hair extensions and body paint applied to improve their overall appearance. Next comes the wrapping. Your whole body would be carefully wrapped up in linen bandages. Hopefully they would have protective spells written on them, and maybe some amulets tucked in as well to protect you from spiritual dangers. A whole host of other steps might be taken to preserve and beautify your body along the way before entombing you, but the main beats were basically the same. At this point we can say that you are a bonafide mummy. Dry and kinda sort of lifelike, but definitely not alive.
I guess I should point out that there is no evidence that any living person was ever intentionally subjected to mummification, despite what cinematic classics like The Mummy (1999) might say. All in all, the odds of that happening are very slim.