【get cold feet】 —lose one’s courage or nerve:

• Do you think he is just getting cold feet, or do you think it’s more than that? We are afraid he just won’t show up at the church.

Note: The expression does not correlate in meaning with the phrase cool one’s heels—(coll.) be kept waiting by smb. in authority, as for an appointment (also: kick one’s heels):

• The doctor kept her cooling her heels for almost an hour.

【hotfoot it】 —leave in great haste; walk or run hurriedly:

• The camp staff expects that once the shouts of the campers fill the hollow, the bear will 【hotfoot it】 out of there.

Note: The expression is not equivalent in meaning to the phrase foot it—(coll., also: leg it) walk; go on foot:

• Several of the wagons became sloughed and the passengers were compelled to “foot it” to town.