For anyone interested in this, I'd recommend the book "One Day in August" by David O'Keefe. He proposes through recently declassified archival research that the goal was to capture the upgraded enigma machine and code books, then to cover their tracks, detonate a torpedo storage facility. This would have basically destroyed the city, but such was the desperation to stem the scourge uboats were inflicting on allied shipping.
It was known ahead of the raid that not all tanks would make it off the beach due to the terrain, but many did and were roaming the streets.
My great uncle was part of the raid and was captured.
Sent from my SM-F741W using Tapatalk