Okay, I got it to work. Actually, two different ways. One way is unnecessarily complicated but allows the ability to carry and use more than one booster, though not simultaneously. It also allows a simpler activation method than aborting a mission. You select "Booster" from your secondary weapons, press the secondary fire key, and your shields and energy start recovering very fast. I also made it so your ship deionizes rapidly, your radar goes offline, and you can't fire any weapons while it's in use. That last one was just by making the booster exclusive-firing and giving it 180 reload. It deals 1 shield-bypassing mass damage over a 32767-pixel radius, killing the 1-armor but 32767-shields/shield-recharge mission ship, setting off the whole deal. When I put it in practice, I found lag affected the 0-armor mission-ship for the second mission jumping in and dying, so the booster kept working longer and recharged more shields and energy than it was supposed to, but the exclusive firing delay lasted the normal time, so I could start fighting while still recharging if the lag was high enough, and then I couldn't lose. The result is, weapon reloads go by 30ths of a second, but whatever controls the mission ending goes by frames.
The other way is effectively as described in my above post, the non-looping way. You can only have one booster at a time. However, you can have more than one type of booster, though it's impossible to have more that 16 different boosters at a time. For practical purposes, if I ever make a scenario where these "boosters" are used, I'd make it so the player can only have one at a time.
And I've stopped calling them boosters. They are now to be refered to as "abilities". This is a totally new functionality for the EV engine, or at least one that hasn't been done before. It's closest parallel that I know of is Lay On Hands or the Weaponshield discipline from RPGs. That is, once-a-day abilities. Superpowers, almost, that only last a short time, or can only be used once.
What I've come up with are:
Superfastjump (mission fails after 1 day so its best use is to escape from combat)
And a whole slew of Superweapons:
Superrocket (very high damage, only get one shot)
Superpointdefense (high damage, rapidfire)
Lockdown (holds target in place, no damage)
Sanctuary (safe zone wherein almost nothing can harm you for a short time, technically a 0-armor carried fighter with no weapons)
Shockwave (big blast radius, high knockback, no damage)
Iceblaster (like a flamethrower but no damage and high ionization, rapidfire)
Ghost (technically a 0-armor carried fighter with a very very long DeathDelay)
Nanites (because if that isn't a superpower, I don't know what is!)
You accept a mission (whether through the BBS or buying an outfits that Sxxx's) and when you want to use your ability you abort the mission. OnAbort it Gxxx's the superpower and Syyy's the ending mission which has a 1-day time jlimit but also a 0-armor missionship that, when it dies, aborts itself, and OnAbort Dxxx's every possible superpower outfits (you could make one ending mission per ability, but this way you only need one ending mission at all.)
Now I hope that when a mission that can be aborted has its timer run out the OnAbort field is evaluated. If it's not, then that kind of screws up my idea of removing the stuff if you land or jump, unless a crön is used too. The one-use fast-jump could work by having its own ending mission that, instead of the 0-armor ship jumping in, has it appear randomly in the system, so you won't see it until you jump or land, and it dies instantly (I think 2 is the smallest DeathDelay that doesn't cause problems.)
Anyway, to make it so you can only have one ability at a time, a simple OnAccept or OnPurchase bit that's cleared OnAbort of the first mission and controls availability should work. Also, if things are set up so an ability can last more than one day, it's important to abort the ending mission OnAccept or OnPurchase of the ability mission/outfit.
Anyway, this new type of object, the ability, runs on the border between a mission and an outfit, and doesn't fit firmly into either category. It uses both, but works totally differently. I'm certain someone will come up with a much more creative use for it than just a short-term increase in combat power, but that's all I've made it be so far, with the exception of the not-strictly-combat-oriented Supercrew for better capture odds. The abilities I listed above run the gamut, and it's up to the individual to pick which he or she wants for the situation.