most probably not. 180ft ~ 6atm. add the 1 atmospheric for a total of almost 7 ATM. 21% by 7 ~ 1.5 PPO. high exertion makes possible for a slight breakthrough and 1.5 PPO with a little CO2 could induce O2 convulsions. if that went unnoticed it might've well been the cause of the outcome. i would not go to that depth with anything more than 15% O2 as diluent, ...
on another note all those "swim studies" are a wash for most of the diving population. the subjects of those studies are highly trained individuals that exert themselves for a living, not the average "joe the office champion". when i was in highschool (former USSR), on cooper test anything under 2.8 km would get you a "scolding" and a barely passing grade (3 on a 5 point scale). it was the hardest part in getting a "straight As" record, mind you i was considered on the wimp side of the class, most of the guys were literally of the charts. if you would make me run it today I doubt i'll get to more than 2.4km.
If you want to err than do it on the side of caution, most of us go out there to relax not to make a living or set records (at least that's how I see it). Human body can take a lot of beating but a little "skip" underwater will most probably put your name in this rubric. It was not designed to run on high PPO and as much as others argue for 1.2 - 1.5 I say keep it as low as you can (reasonably close to the normal .21), rise it only to the strictly necessary in order to avoid "unreasonable" decompression schedules. There's a reason they teach you the "oxygen clock" in Nitrox 1, even if nobody says it loud and clear.
None of this post was meant to be rude, impolite, or to insult anybody - if you chose to take it as such don't throw it on me - english is not my best way of communication.
a called of dive would have just upset some people, nothing more. while things might have played this way for the victim even on dry land, in my mind there's no doubt that exposing himself to those conditions was a factor.
The autopsy will say something - it has to, but, how accurate will it be on a body that was brought to surface after being to some degree saturated at 7ATM is not certain - i would not put much value on it.
may your adventure be a lesson for others and not a mark on you (shame on those who see it like that).
RIP brother