Absolutely great! That kind of vision is very rare actually. It's an original idea ! Maybe a little darker of more contrasted would make it even more credible as a cave.
Sanctuary...Conventional distance from home planet, at two million light years, apart from the dimensional space time altercations. The journey takes an immediate shift pinion, allowing access to this galaxy, unaware of the simbionic engine and pilot failure aboard the vehicle by an newly introduce mutated abstract virus. Landing was problematic and although the geomagnetic system functioned appropriately, it did destroy the surface structure of the ship, as with any contact to home base. This is the remnant hold, and the planet's surface is hostile. Now for their consequences... they are appropriately two million light years distance in real time.