It was decided that Frank should endeavour to make his escape from the cave that night. It was in the act of passing the sentries, posted at the entrance, that the bulk of his danger would lie. Once the boy succeeded in getting away from the cave, his absence would probably not be discovered until the following morning. He would, in that case, have several hours' start of any pursuers whom Cheong-Chau might think fit to send after him.
Frank had already considered the contingency of making a dash for liberty. He had, so far as he had been able to do so from the interior of the cave, studied the lie of the land. He had noticed that the sentries were not particularly vigilant and that they were armed with old-fashioned, out-of-date fire-arms which they possibly knew not how to use. One of these was a Martini-Henry carbine, and Frank had on one occasion seen a Chinese trying in vain to lower the lever, which was so rusted on to the lock that it was quite certain that the breech could never be opened.
Immediately before the entrance to the cave was the huge boulder, or rock, which has already been described. On either side of this rock a sentry was always posted. But these men did not necessarily face the cave. Indeed, as often as not, they looked the other way, interesting themselves in the wide panorama extended before them. None the less, since the two passages on either side of the boulder were very narrow, one could never hope to pass without being seen. Escape that way, therefore, was impossible without a struggle, which meant that the alarm would be given and a party would immediately start in pursuit of the fugitive.
This was what Frank most wanted to avoid. He knew that his attempt was doomed to failure if he did not succeed in getting well away. He therefore examined the rock itself, and saw at once that it would be quite easy to climb to the top of it. Since he could not pass _round_ this obstacle he would have to go _over_ it. On the other side, as he knew, was the steep mountain slope descending hundreds of feet to the bed of the valley. Whether he could climb down the slope at all, much less do so silently, so as not to be overheard by the sentries, was another question. He was resolved, however, to take the risk. It was clear that there was no other alternative. It was a perilous business, but he must make the best of it, trusting to Providence, as well as his own agility and presence of mind.