Buoyant ascent and bends? If your are within NDLs, as you should be, the possibilities are remote.Buoyant ascent--maybe the bends, but you probably live. BCD breathing--infection, loss of buoyancy ascending, but may work. Atl. air ascent with buddy--works great in the pool, but panic at some point could create real problems in a real emergency, so I've heard.
Panic during an alternate air ascent? Possible--but do you think it is more or less possible than a panic during buddy breathing? You will give your only regulator away to a panicked diver and assume you will get it back soon?