Complex sentence: While everyone else goes to Jill's rescue, Moses engages in combat with the M.A.R.K.-13; he manages to cripple it, but is injected with the cytotoxin in the process.
Split into simpler sentences: While everyone else goes to Jill's rescue, Moses struggles with the M.A.R.K.-13. He manages to cripple it, but is injected with the cytotoxin in the process.