High security does not mean safe. The Only safe system is the starter systems and the sisters of Eve arc. And those are supposed to be safe from other players being jerks. Hi sec though, is not safe sec as you call it.
Unlike low/null/worm space, CONCORD gets justice for wrong doing, they don’t protect. But it’s for PVP wrongdoing not PVE.
Low sec has limited security and it’s mainly faction police, not CONCORD.
Your friend either took his time warping away or as mentioned used autopilot. I’ve entered systems with triglavians on gate in my Battleship and can warp away.
CCP does have plans coming up, though they were vague in their message that CONCORD is fed up with intrusive capsuleers, so not sure what that means for hisec as of yet.