FWIW, the asylum mission is one of the best opportunities to train your agents on the side, because the ghosts in there won't hurt you. The most important thing is to keep track of all the bug-eyes so they don't wake up and start wandering around. I usually pile them up in a couple of places or blast the remains with a grenade.
Melee them with stun sticks (training melee is the most crucial thing to make most agents ready for martial arts training), use pepper spray on the bug eyes to get bravery (if you have unlocked pepper spray), etc. You can also ineffectively shoot a couple of them if you need firing practise. You can also preprime a couple of grenades at mission briefing and throw them at the big ghosts at turn 1 (so not to mess you up if someone panics or gets stunned).