Banner was not sure how he had ended up wandering a dark cave with only a candle as his light. He remembered entering the cave with his research team and doing some measurements, but after that his recollections had turned into a blurry mess up till the point he had become aware of his surroundings and the fact that he had only a couple of candles and a lighter on him. Only the echo had answered his calls, so it was safe to say that he was all alone.
He did not know where the candles had come from, though. He certainly had not packed them with his gear, let alone put them in his pockets; the wax would have severely stained them and he did not want that — this was his best (and only) suit and it had cost him multiple months’ worth of salary, an amount of money he was not looking to spend in his clothes… ever again, actually. Sure, he was doing work that had a high likelihood of getting his clothes dirty, but dust and mud were far easier to clean than wax.
Nevertheless, he was alone and hopelessly lost. He found himself even doubting whether or not he was in the same cave anymore. The blurred memories did not give him any answers, so all he could do was wander around and hope that he could make it out. Finding water along the way would be beneficial for his survival as well.
Otherwise, he would die of dehydration before long.