"Look me in the eye!"
Apone is the military leader of the Marines. He is not that obsessed with keeping military order, but more interested in life's little treasures like his cigars and eating and sleeping. But the Marines have respect for the old warrior and they don't question his rank. He is one of them - a good old boy. And for him, they are not just some lousy, no-good jarheads, but good kids, able to do their stuff if someone gives them the chance.
Out in the field he is calm - probably of his long experience, and he puts the safety of his crew high. But - he is brought down during the confused battle scene under the atomic powersource and is assumed dead. But ol' Apone had another, nastier destiny. He wasn't dead - only near death and was used as an incubator for one small burster. When the crew learns this, they want to go back and get Apone, but Ripley tells them that he was being empregnated and had no hope what so ever of survival.