Q. Titurius Sabinus made a fatal decision in 54BC when he agreed to come to terms with Ambiorix. Ambiorix agreed to let Caesars 14th Legion abandon their winter quarters under the assumption that the 14th Legion would have safe passage back to their lines. Sabinus who trusted Ambiorix as a former friend and ally to Caesar agreed to terms in belief that Ambiorix would hold true to his his word. Unfortunately for Sabinus the legion was attacked on the trail no less then 2 miles from their winter quarters. The 14th caught of guard and panicked held their ground and formed several orbs (just for you Mike) to hold off the onslaught. Fierce fighting carried on from the morning into the afternoon until Sabinus believed he could talk sense into Ambiorix. As both sides restrained from fighting for negotiations Sabinus assembled his entire high command with the exception of second in charge Aurunculeius Cotta to meet with Ambiorix and his followers. As Cotta looked on from within a orb he watched in horror as Sabinus and all the command staff were cut to pieces by Ambiorix and his men. Ambiorix then resumed the attack on the Romans. Cotta who was very critical of Sabinus decision in the first place fell in battle while a small contingent of Romans were able to make it back to the fort where they decided to commit mass suicide.
This is my rendition of those events. I know the armor doesn't match up since this was before Imperial times but I was always fascinated by the story and appalled by the decision making which led to the 14th Legion being wiped out.