For this to work, LaGeurta had to have stolen Debra's gun, and they had to leave it in Maria's hand when they left.
LaGuerta was completely fucked unless the Morgan's were psychos,
This was her hail Mary to save the day in the minutes but she fumbled.
It's a pattern.
A downward spiral but certainly a pattern.
Good Lord, she stole 20 year old evidence from the locker and planted it in Dexter's car which was refuted in minutes... Maria is way less smart and competent than she thinks she is which means that further more glorious fuck ups are par for the course.
A psychotic fixation on Dexter that will not quit.