So how about this?
Hero sneaks into the house, listens to the whole thing. Luftwaffe General demands they arrest the big bad, causing everyone on the fence to pick a side, creating a Mexican stand-off. Big bad explains the situation as a no-win situation to all involved, so he allows the General to leave, without really explaining why but explaining that the General cowardice prevents him from staying there to stop him.
Hero signals the other three to pursue the General, but only his lancer and the big guy do hile the smart chick stays. He doesn't intend for them to do anything useful, he just doesn't want them to be drawn into the unwinnable firefight he's about to start.
The coup seems to be thwarted, but then the other loyalists begin to have a change of heart, partially due to the Luftwaffe General's penchant for career-orientated backstabbing. One by one, they switch sides, and the big bad reveals he has measures in place to stop the General from reporting them.
The hero, who's a teensy bit suicidal, wants revenge and recons his superiors don't want a group of competent General messing up matters when they're so close to victory in Europe, decides to light the powder keg. He walks into the room, pretending to be one of the officers' escorts (everyone assumes he's someone else's) and slips in a bomb, similar to an earlier scene that saw his platoon wiped out. He's rebuked, but not before he's seen the big bad.
The bomb goes off and violent confusion ensues. Through confusion, luck and the intervention of the love interest, everyone is dead, but the bad guy slips away, wounded. The hero and his LI walk out too.
The lancer and the big guy run into the fleeing General's car as his escorts, who had been bribed by the big bad's men during the summit, stop the car to kill their boss. The good guys stop the hit and the lancer, who is a German defector, gets some intel out of the dying General.
Little does the hero know he's accidentally allowed the big bad's real plan to mostly work. The intel retrieved by the lancer and big guy is later doubted by their new CO, due to the nature of the intel as well as their dubious personal histories.