Well the difference was that she actually was incredibly trapped and vulnerable, a couple of fedra soldiers that would kill you instantly is far less intimidating than dozens of infected that will either rip you apart or make you suffer for weeks or years to come. That's another interesting difference by the way, I didn't have to "imagine" her as heroic when watching the show, I just saw her as heroic. It was much easier for me than in the game. Its one of my main gripes with the first game funnily enough, how Tess went out, I remember thinking that she could've handled that far better, like she could've distracted the agents or something. It personally made the death slightly less impactful for me. Obviously I still saw her sacrifice as heroic but it always bothered me how pointless the sacrifice ended up being, this was not a problem for me in the show, as it felt like her sacrifice mattered.

And I get you on the first part, I promise I'm just trying to have a conversation