That only works if you can actually tell if it misfired or not - if you're administering it to someone else, you may simply not be able to. With that, part of the problem was that the misfires would deliver some of the drug but not all, and only sometimes would completely fail to deliver any of the drug. Telling if you got 50% vs. 100% would probably be tough - and even if you could, if you took two because the first gave you 50%, you might end-up getting a big overdose or still get an underdose. So having multiple of those pens really just doesn't solve the problem if the pens themselves are unreliable.
