There are so many little details I love about Mass Effect, but one of my favourites has to be when we see the squad boarding the Kodiak or the Normandy after a mission. Each and every time, Commander Shepard is the last one to go. Even if she reaches the ship first, she'll stop and turn, providing covering fire or encouraging the squad to get on board while she waits, because as the Commanding Officer she can't board until her crew is safe, and it's her responsibility to make sure that happens. We see this dynamic on Earth too, at the start of Mass Effect 3. Anderson is planning on staying behind anyway, but unlike all the other times, Shepard doesn't hesitate to board first - she's climbed up and into the Normandy before Anderson even reaches it, because she isn't the highest ranked soldier - this time her responsibility is to get to safety so that her Commanding Officer can follow. Likewise, her squad don't hesitate to board, or wait for her - they know they need to get to safety before Shepherd will follow.