Complex sentence: He climbs into the saucer and flies off, but K and J arrive as he does so, and pulls out space weapons to shoot the saucer down, they do so, causing it to crash through the Unisphere.
Split into simpler sentences: He climbs into the saucer and flies off, but K and J arrive as he does so. K then pulls out space weapons to shoot the saucer down, causing it to crash through the Unisphere.