hello. i found out how the triumph works after tethering like 15 enemies at once and killing them with grenade launcher, even getting massacre medal it didnt pop what i did: yesterday went into private game (normal gambit not prime) . top tree single tether. shot the whole wave to low hp. shot tether into ground. they all died from getting tethered. i didnt shoot a single bullet. the getting tethered did dmg and every tethered enemy died and the medal popped. but in private game it didnt count for triumph so i had to repeat this in matchmaking. LFG people werent reliable, kept killing even though i told them to keep them low hp at a specific wave. queud solo . orpheus rigs , Light Reactor + Fusion Rifle for quicker super. Took me like 12-15 arrows to get a group of like 8-10 cabals tethered, shot a couple of them low hp previously and it popped the medal.. Finally..

I think its a bug too. Tried 20 times and still cannot get it.

you got it yet? i'm trying currently but it doesnt work somehow. Triumphs are way too unclear in the description.