The zombie fell down from the door on the left side of Sumi.
She did not expect to see that zombie so close to her face. She was startled but she kept herself calm. She knew shouting would just make things worse for all of them. She didn't want to make things which were already terrible, worse for anyone and herself too. Because if she made a single sound the zombie would know about her exact position.
He was blind and couldn't tell where Sumi was so he just stayed on the ground looking everywhere in the room.
Sumi did not move at all neither she made any noise. She was looking at every single movement made by the zombie so she could be ready if it was time for her to flee.
The zombie kept on making sudden movements. He didn't make any kind of noise and was trying to observe his surroundings.
Sumi's heart was racing at that movement. She was fearing for her life. She wanted that zombie to go away from here as soon as possible but even she knew it wouldn't be that easy.