Possible Clues:

• Track up mountain out of order for period in US, say
• Negotiate track up mountain, perhaps
• Period
• Period, say
• Stop at the end of the sentence perhaps
• Exclamation point, e.g
• Any of the groupings of circled letters in this puzzle
• Slash, say, ludicrous amount, in cut that's put in place
• Terribly traumatic on getting into aggressive music for a period in New York, perhaps?
• Scramble up mountain track, then maybe stop