by engelstein
1. Locks remain from turn to turn. You can lose them if the ship moves through nebula spaces. This tends to happen at the worst moments, of course. A viable strategy can be to put some energy in sensors onto key targets that you have already locked as insurance in case Helm is taking you through nebula.Superlocks can be critically important for tractor beams, and for the harder enemies.
2. Your sequence on breaking locks is correct. Enemies will try to reacquire you, and will automatically do so if you hit them with a torpedo.
Breaking Locks is useful if you are trying to get away from someone. If you are planning on attacking them that turn, or if you are planning on staying close to them, it is usually not worthwhile to break a lock.
But if you are moving away and don't want someone to chase you, breaking locks can be really valuable. For example, in Mission 1, if you grab the first or second crystal but have not killed the enemies, you can break lock with them as you head off towards the next crystal.
Remember, in most missions you do NOT need to kill all the enemies to win. So doing what you need to do and running away can be good.
Sector Scans and, if you are playing with the Advanced Systems, Cloaking can also be really useful depending on the situation.
In training mission Alpha, because of the time constraint of only six turns, getting a few superlocks can be very important.
3. An enemy that gains a lock on the players gets to move and fire immediately.