I think this is a bit harsh? That and not particularly realistic. The fact is, Brian is not especially elite all things considered (best case, he's piloting a Legionary despite his inexperience thanks to prior piloting training, but standard Legionaries aren't actually invincible on this battlefield). He's not part of ParSec and it's even higher gear standards. And he's caught up in a battlefield where a significant portion of forces were shot down just in transit (which would kill anyone, Power Armor or no). Then there's the swarms of Batarian pseudo Husks, artillery, and heavy power armor with heavier weapons. The fact is, having plot armor is probably why Brian only had a 10% chance to die, and even then he might have been saved by Revvy if she didn't nearly crit-fail. The rest of the landing forces didn't have odds nearly as good as that, and might have even been effectively wiped out without the last second (and evidently too late for Brian) 95 on Revvy's remote Mk 2 suit.
And frankly, this is all assuming he's got Legionary armor (the thing reserved for elites in the SA infantry, and not something Brian could have possibly qualified for except by a special exemption due to him already having training with it...an exemption we don't even know if he has.) If he's just a skilled grunt? 90% chance of survival and a backup sugar mommy roll is generous when it comes to a deployment this fusterclucked.
I think my only issue with this roll series is really why a relatively new recruit like Brian was even deployed in the initial wave of an operation as hazardous and important as Torfan should have been projected to be...but even if he's not an elite, he did join at least a year or two ago so he's not untrained, and a call for volunteers was made...and pretty much his oldest character trait was wanting to be a hero. I'm not even sure a background roll would be justified for that, just to see if he was even on the invasion fleet to volunteer for the deadliest drop. And even then...well the SA was pulling out all the stops for this operation and ParSec was already doing a great job guarding the colonies. There are probably more SA infantry here then anywhere else.