It's too easy to dominate with a swarm with the current defib mechanic. Doesn't matter how many you kill, if you are outnumbered, you get pushed and your kills are negated by enemy defibs. You can do it in sneak, it doesn't de-sneak you, no AP penalty, instant Jesus ressurection with 100% chance, very low Doc requirement.
My suggestions to try balance this:
-Doc reqs, auto defib - 150% doc; manual - 200% doc.
-De-sneak the user on use; the use starts a 10 second timer that can be interrupted by entering sneak,moving,shooting or any other action; if the timer is not interrupted, the target is ressurected and the defib user gets -200ap penalty.