That's a thought. They have a small operation at the Hotel Barracuda right across from Mega. They only allow pick-up of their divers there; I know because I tried to pay them a fee to allow LU pick me up there.
I think you'd be within walking distance of a Dive Paradise location to get on one of their boats, but I'm not sure. Since I was already looking, I just added this as a potential. Someone else on here would know better if they're walkable from downtown, or what a taxi would cost to get to them. Could be $6-$8 per day taxi from downtown? (Hotel Coz?)