i imagine theres a sense of pride in why people sometime appear to choose to wait til theyre alone before going...
as well the desire to save a loved one the heartbreaking sight...you lso yourself dont know what will happen to you...i mean physically...depending whats wrong with you of course...will you scream, gurgle, dribble, convulse, etc etc...and i suppose some may not want people to actually see that...the fear may make it something they prefer to deal with alone...
i realise at that point things like that should be the last thing on your mind...but some people are very private and proud and care a great deal how they look an what people see...
i mean its bad enough having visitors when you are ill...so i imagine this is worse...
so maybe it just happened how they want it, and so dont feel bad...