1)
Who should flee?
1.
Rashi: Yisrael.
2.
Radak, Malbim: People from other nations who were in Bavel [Radak - for business], they should flee, lest they die amidst the sin of the city.
2)
What is the meaning of "Tidamu"?
1.
Radak, Malbim: It is an expression of being cut off, like "v'Nadamu Ne'os ha'Shalom" (25:37).
3)
Are "Nekamah" and "Gemul" two different matters?