Adding this init made armour invincible?

[mikuinstallgentoo 0]

So I was looking for a way to "double health" of a unit, or something to that effect. It seems you have to lower the Damage effects of all weapons dealt to the unit because you can't add HP. So I came across this script.

this addEventHandler ["HandleDamage", {(_this select 2)/2}];

and it seems not to have double damage required for the unit to be killed. I tried center mass with a ballistic vest and it seem to tank 6.5 rounds, then I tried the head and it took one shot, maybe two, maybe not, it's iffy on what it wants to do on that part. I put it on a tank, seems to make the tank invincible. one time it appeared the crew died or something so I added the script to the individual crew members which seem to also make them invincible. Is there a clear cut way to make units marginally stronger without making certain parts invincible? I tried using a titan at turret on a Merkava and those viper rifles on (I think) a linovan Ballistic vest equivalent of a mod (csat replacement project I think) for replication sake.