Oh, I didn't know that! I can't get to the citation, but per Wikipedia [1] Hydrophilidae, the family in which this beetle is classified, do have that capability. Whether even with an air bubble they can hold out long enough is a separate question, as is whether their also-mentioned ability to extract usable oxygen from ambient water would be helpful in this environment - but being able to carry air under their elytra would certainly improve their odds.
