Frag grenades don't wake up dormant mech clusters. A single pawn can grenade down all mech capsules and cluster's unique building without waking up the cluster. Turrets only wake up when they take grenade damage. Two pawns throwing grenades at the same time can take out turrets before they can retaliate.
Will check, thanks.
You don't need even frag grenades for that.
Mellee works too, so long no active mech building get hurt like turrets, the cluster stay passive.
I haven't tried melee but if you grenade a turret it goes down to 20% hp and wakes up while the rest of the cluster keeps on sleeping. The only way you can wake more then 1 turret is when the turret your fragging down begins to detonate and its explosion damages a nearby turret, that damaged nearby turret will be the only thing that wakes up. Now I don't know if melee triggers detonation or not but turrets have a 50% chance of exploding when reaching 20% health, with that said if you lob two grenades at the same time you maybe be able to prevent a detonation all together as the turret should die 100%->0 in a single swoop. Allowing you to surgically do whatever you want with the cluster whether it be taking out the defences and leaving the mech assemblers alive or taking everything out and collecting the unstable power cells with ease.
Fixed for the next update, thanks for reporting!