Deleted the prior scenarios because I was including a full nine innings of outs for the US, but if Colombia wins then the US wouldn't be at 27 outs, they'd have 24.
New scenarios -
US wins and they advance as the 2nd seed. Mexico has already won the group.
If Colombia wins (non-walk off or walk off with zero outs to make it easy):
By three runs or fewer and score is 3-0 or less, US advances.
By 4-1 score, goes to the earned runs allowed per out tiebreaker between US and Colombia.
By two runs or fewer and score is 4-2 to 8-6, US advances.
By 9-7 score, goes to the earned runs allowed per out tiebreaker between US and Colombia.
By three or more scoring more than 5 without allowing 10, Colombia advances.
By 4+ without giving up 10 or more, Colombia advances.
By 11-10 score, goes to earned runs allowed per out tiebreaker between US and Canada.
By any score with Colombia 12+ and US 10+, Canada advances.
As said before, these scenarios do introduce the South Park Little League situation where the US could try to lose on purpose in order to ensure they lose by less than three or four.