Ok, but let me ask you a question. If that 50 malfunctions- what are you supposed to do? You're supposed to correct that malfunction that's what. And if that action doesn't come second nature to you- you haven't trained enough with that weapon and are therefore not qualified to operate it.
A 50 malfunction is fairly simple to correct (assuming it's not the timing or headspace). We're talking about pulling the charging handle here- not dissecting the weapon.
I speculated on another thread that the operator might not have had the weapon on auto fire. For those that don't know- there is no safety switch on a 50. It's either ready to fire or it isn't. You've got single shot or full auto that's it. If you don't twist that little catch and put the weapon in full auto mode, that weapon will shoot once and stop (like duh). I've seen soldiers get flustered when that happens. Maybe it happened here.