Not to sound too hoitytoity but dive masters don't always know what they are looking at. At least in my experience, they have been good at what I needed them to be good at: being the dive master and fiddle faddle with the tanks and regulators and other dive-ish technical mumbojumbo, but as far as the biology of the reef was concerned, some were barely past "look at all the pretty fishies and stuff." If the dive company had a marine biologist on hand that might be a bit different but then again, I'd be a bit baffled that a marine biologist would have trouble identifying a condy (if not C. gigantea I'm thinking this is surely in the same genus).
Definitely not Entacmaea quadricolor (BTA) although surely some similar features (but then, condys do look like this). But E. quadricolor is strictly Indo-Pacific range - unless a very rare colour specimen hitched a ride with a lionfish, I'm thinking "not BTA" is probably a pretty safe bet to take.
