When Mr. Bluett throws the bucket of water to put the fire out, the water all misses the flames and ends up soaking Pike. However, the flames immediately go out anyway, indicating that the fire is in fact fed by an underground gas supply.
When the Army is eating by the lake, the Reverend tells the Yeatman to let the boys out of the tent. Yeatman salutes and then runs to the other side of the tent. While he is running he trips over a tent rope and is falling. The camera cuts away right before he falls and when the camera switches back, Yeatman has recovered.
The German aircraft seen by the men must have crashed in the lake- otherwise the crewmen would not be in the raft in the morning. Nobody hears a sound. The crewmen have paddles, and had ample time to proceed to shore to hide, but they don't, and none of them are wet.
The three airmen have been sitting in a dinghy all night despite being able to manoeuvre it. In reality they would have simply either swum ashore or paddled ashore long before dawn.