What makes this thread so hot is the "pretend snuff play" or "pretend necrophilia"
That wozls be completely ruined if the watchman were to actually kill them.
If he catches them now, he can demand whatever he wants, so I would demand they keep playing, but to my rules. Then simply watch them perform.
Obviously they have to take it a bit further. Penetration is a must. And a bit of abusing the "dead" would be neat, too.

All things, that the kids wouldn't dare do to each other on their own, but would secretly find hot, too.