That feel when you can follow that entire conversation in in the first webm.
>I got to massively extend
The guy wants to break out of the engagement area to give himself some space to work, distance is also useful for defeating SAMs which is what they're doing here.
Radio call for firing an AGM-65. This is relevant because the A-10C has a Missile Launch Warning System that will trip when it detects any launch, so calling Rifle alerts friendlies that the MLWS signal in that case is responding to a friendly launch and they don't need to go defensive.
>I don't know if it's an SA-8 or maybe an SA-15
The guy is identifying the target as one of two different kinds of Surface to Air missile launcher.
>Can you get a TGP on him?
Second voice is asking first to use his targeting pod to locate and visually track the target.
>SPI's on, Broadcasting
SPI is Sensor Point of Interest, and is a designated point that your systems are currently storing information on, you can slave sensors to SPI instead of having to manually find a spot every time you make a pass. So he's saying that he has got the target set as his SPI, and is broadcasting that over the datalink. This means that in the rest of the flight, his SPI is showing up on their TAD (Tactical Awareness Display, moving map with extra features) and they can slave their sensors to his SPI.
>Mark is set.
Could mean two things, but looking at the TGP display narrows it down. What he's saying is that he's set a markpoint. Basically a waypoint of sorts which makes it easier to put the SPI back there later if you move it somewhere else in the meantime. It's essentially permission to fully disengage because the target information has been stored away for a second pass.
The rest is fairly easy to follow. Missile launch, going defensive which is just brevity for focusing entirely on evasion, dumping countermeasures. "Lead status" is just the wingman checking in on how the flight leader (who went defensive) is going.