I remember long ago, a discusson on here about an "injury sidequest." I wrote up a scenario that I thought would be pretty cool. It's way back in the archive, may have even been taken out when the board had trollery and got erased. It was before Skyward Sword was even announced, just a speculation of "what could happen in a future Zelda game."
The scenario I and other folks in the thread came up with was: Link defeats a boss, but in its death-throes (a small cutscene), the beast lands a posion or magical sting into Link. Whatever Partner/Exposition Fairy he has for the game (or perhaps just game-narration if he's partner-less this time) tells you "You have been poisoned! See the Professor/Doctor/Shaman quick!" Then, it's a race to get to a doctor-type character you've met earlier in the game. Then, it becomes a bit like Midna's Desperate Hour in TP except that there *is* an *actual* time-limit between the poisoning and Game Over. Throughout the ordeal, Link starts to slow down and stagger increasingly as the clock runs down, plus the scenery will start fuzzing-out, shifting from fuzzy to clear. If you go to first-person view, the world will fuzz. Once you get to the doctor, you get another cut scene where it blacks out, then Link wakes up in a bed with the doc telling him "Almost lost you!" After this, Link is given the Heart Container he would normally get from a boss as a healthy-gift from the concerned doctor.
Necessary rules added to the scenario to make it work:
Bottle items do not work. That means no fairies, no potions, no milk, no soup or any other healing items for the duration of this drama-scene. They're "X-ed out," faded, like items you cannot use underwater when you are underwater.
If you Game Over, you're sent back to when you defeated the boss. You don't have to defeat the boss again. This is like most timed-events in Zelda, you're sent back to when the clock starts, you don't have to do anything leading up to it over again.
The heart-meter/life-meter does not matter. If you have 8 full hearts at the beginning of this, it's the same as if you have two full hearts. It's a time-event. However, at the end of it, if you don't make it to the doctor in time, your hearts will empty out dramatically when you die. Woosh! After that, you'll be sent back to the beginning of the poisoning with the customary three hearts to punish you for dying. Again, your hearts aren't going to empty out as you're running, they'll just "woosh-out" when you fail to meet the time limit.