The issue will be what caused the death.
If I got a heart attack and was brought to the hospital
immediately, and the hospital failed to use their expertise and
equiptment to save me, can my family sue the hospital for failing
to save me.
Can the family prove that the life guards can definitely save
the man but did not, and therefore is the cause of his
death.
The swimming pool does not have any extraordinary danger that
the swimmer must be warned about. There is only drowning, and every
swimmer knows that. He went swimming at his own risk.
The role of the life guards may be examined, but they did not
cause the death. The question will be :"Did NUS provide an unsafe
swimming pool?"