Power outage for 2 seconds killed her? I may be mistaken, but I highly doubt you can die from being disconnected from life support for a measly 2 seconds. Unless that time frame wasn't about the lenght of the outage alone but was just mentioned as the delay to the other announcements.
Next thing, a hospital would usually have an emergency generator (or however you properly call them in english) which would kick in in a power outage bringing some much needed electricity into the system, giving the hospital staff time to resolve the power outage issue.
So unless this is some really convoluted way of hinting at someone intentionally unplugging her from life support, I'd say the author did an awful job coming up with a reason for MCs death.
That aside, I like the rest chapter though. Even if it ticks off the typical Isekai start, seeing how she wakes up in a (semi) unfamiliar place, lacks common knowledge about said place (specifically how it changed compared to how she knew it) and is in denial of her situation at first, thinking it must be a dream.