Because you never intended to overfly the rig; you used the lowest ( approx 2.5 nm) scale and you made a decision at 150' and 0.5 nm or 200' and 0.75nm having already made an offset to avoid the blob. If you got an automated AVAD (yes the boringly simple one) call-out, and not visual with the destination, it was further offset, pull power and climb to MSA. eGPWS was designed to avoid terrain and published obstacles for onshore work ...... database, loss of situational awareness, confirmation bias