Why should she close the door?
Rashi: It is honor of the miracle to be covert.
Malbim: (a) Ayin ha'Ra should not take effect. (b) An improper person should not come close, lest due to his bad deeds the conduit of influence (Brachah) cease.
Why did he say "veha'Malei Tasi'i"?
Rashi citing a Midrash: Clear the full Kli from in front of you, and bring another Kli in place of it to fill it. Do not move the flask of oil, for Hashem makes it like a spring, which does not more from its place.
Radak: She will not move, and not the flask in her hand, for the miracle will be only in the place where it begins. Malbim 1 - from when she tilted the flask to pour, she held it that way until the miracle finished. She poured without ceasing.
