Well as for the o ring We told the shop in the morning and they said they replaced it. The tank continued to leak and at the pool the instructor replaced it one more time and disconnected the yoke from the first stage and made a comment that there was an oring missing from between the first stage and the yoke connection he put it back together and the leak was less but still leaking.
Generally,small leaks are not a giant deal (they should be fixed though), however you just moved the bar up a notch with removing the yoke.. on most regulators you need either a special wrench or just a very large one to remove the yoke..and if you have that, the odds are you have the o-rings to correct the issue.
It does raise the issue of what else might be wrong, sends the wrong message and puts the student in a terrible position of having to choose between what you are being told and what you think is right... regarding life support equipment. It also leads to one being unduly worried during a dive.
Just so you know, tank o-rings leak all the time... and sometimes (not often) they also get extruded out..and that little leak goes to a huge giant leak. You kind of want to avoid that. The yoke missing an o-ring just leaks.
The octo leaking, if it is just an adjustment, is a very quick fix.. if it is a worn out seat, then it needs to be rebuilt... problem is.. you have no way of knowing which it is.
A reasonable answer to either would have been to use the gear in the pool and have it fixed for the next use.