I wasn't there, but this is a fairly common occurence.
DC the reason they didn't get shot is that someone in a bomber had knocked down the ack earlier.
Then as soon as they captured the base, the ack regenerates. Realize that this is now THEIR ack, and you are right in its firing envelope.
Thats why it killed you.
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Vermillion
**MOL**, Men of Leisure,
Dicta Verm: "Never give the suckers an even break!" or translated "Never engage without an advantage"