Finding an 'indoor' space in the wilderness was a rarity, and the two researchers were pretty shaken by the unexpected danger, so they ended up staying in that cave for a few days.
From the research point of view, it was also a good thing to test how long could the device manage to operate non-stop. And rather than kept on walking non-stop as they did on the second day, it was better for the researchers to distract their minds by compiling data and conducting experiments instead. There were lots of transformed vegetation that could fill their schedule for years. Not to mention the remnants of the Earth and Wood Specter that they had never seen before.
It was another weird thing that Zein had never considered; a base inside of the Deathzone. A base so good they could even shower. He had a feeling that rather than the thought of experimentation, the researchers cheered up better with the thought of being able to finally douse their bodies in fresh, purified water.