Continuity mistake: In the opening chase with the seaplane the fuselage changes shape from being pointed at the tail end to being square to load the jet skies and as they crash through the exploding bridge to being pointed again.
Plot hole: The seaplane should have a watertight hull so the two jumping out the bottom makes no sense when they should have used the same exit at the rear of the plane that they loaded the jet skies with.
Continuity mistake: In the scene when the bad guy drives through the front of the airport, he crashes into a pillar. The truck stops flush with the pillar. In the very next shot it is a foot or so away from the pillar.
Continuity mistake: When the men are being attacked after spending the night in the abandoned town, the horde of people attacking them are all in dark colors such as gray and black. If you watch carefully, you will notice one man in white attacking. This man is shot down and dies, but a few seconds later he is alive and attacking still.
Continuity mistake: At the beginning, when the Expendables and Trench are leaving the interrogation room, we see Jet Li along with his main weapon leaving with them, but in the next shot, he picks up his weapon and leaves the kitchen.
Continuity mistake: Just after Billy dies, Barney says "let's take care of him" and Toll Road puts his cap on. In the very next shot as they walk away Toll Road's cap has disappeared.
Continuity mistake: When the bad guy's convoy is coming towards them, the good guys shoot a hole in the front of the truck right under the windshield. Once the bad guys crash the truck, the bullet hole is gone.
Continuity mistake: In the bar Gunner writes down Einstein's theory on a napkin. He writes it near the top on the napkin, in the very next shot it is closer to the middle of the napkin and the hand writing changes.
Continuity mistake: When the shootout starts in the airport, the Expendables shoot some bad guys and duck behind a service kiosk. We see Chuck Norris shoot one villain from the second floor behind and above the Expendables. Moments later, when the Expendables advance into the airport, they shoot several bad guys that are on the same level Chuck Norris should be on. Chuck Norris apparently disappeared.
Answer: "We keep it light" refers to their mood. They joke around and tease each other and have fun. "Till we go dark" is when they get serious for killing. "We go pitch black." Meaning as dark and brutal killing machines as possible.
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