1)
What is the meaning of "va'Ya'amdu Ish Tachtav"?
1.
Malbim: [Bnei Yisrael] stood in their place around Midyan's camp [and the latter panicked].
2)
To where did they run?
1.
Malbim: One ran this way and another ran this way, amidst panic.
3)
Why did they blow Teru'ah?
1.
Rashi: This was a Siman to travel and flee.
2.
Radak: It was [due to feeling] broken and afraid.
3.
Malbim: Some blew Teru'ah of war, and some fled, for there was confusion among them.
