I'm sure "even Marksman" would make me look like a newb 
I wish I understood what that means.
On topic:
HowlingSiren and I had a mutual yen to play some Platinum earlier this week. So we went Plat pugging for a while.
Low: We made three lobbies, got Reactor (or Hazard) Collectors three times in a row 
One of the Reactor Hazard games gave us the first wave 6 device inside the reactor.
Low: The enemies all spawned on the device. So I ran to the door, saw everything in there, hit the button and went to run round. Then I saw "HowlingSiren is down". See, she had run into the reactor and nuked the enemies just as I was hitting the button....
High or Low, depending on point of view: she raged at me for a full minute. I could still hear her with my headphones off 
Low: I don't think cooking someone in the reactor counts if it's not fully intentional, does it? (Need the official BSN ruling on this one.)
Weird: We had an AIU, with no one else using grenades, and two nades per box all over the map. She still spent most of the game on her face.
Über-low: We got mission fail on wave 10, with just the GI left alive (the rest of us being out of gel by then) and one device to do 
High: Next we trolled HamleticTortoise in to play with us, and we three went as SI snipers. Tortoise and Siren made the game into easy mode. I simply put Proxy Mine everywhere and killed the seeker swarms 
Bonus High: right after that last game, Smehur pinged for a game, so she joined us and we four went as a full Geth team and stomped Reapers on Giant (no, we didn't preset that either!)
Great games, everyone. And, Siren...I'm still sorry, OK? 