Complex sentence: Chakotay's health gets worse, and the ex-Borg offer to connect him to a joint mind to heal his injuries, and he reluctantly accepts where he sees a montage of their memories.
Split into simpler sentences: Chakotay's health gets worse, and the ex-Borg offer to connect him to a joint mind to heal his injuries, and he reluctantly accepts. Once part of the hive mind, he sees a montage of their memories.