Playtime activates at anytime for whatever time it lingers, people have tried to notice any patterns but have failed, you can only gamble when it starts. If you stayed in the light and the playtime ends you still will be affected by playtime, the time you spend in the light, it doubles to wear off, , making some people forever stuff in playtime, cause when you're in your playtime form, you're always enticed to stay in it and to pull others in too. If you managed to find shelter or stay in the shadows and put lets say one of your limbs in the light only whatever touched the light will be effected, it's not infectious.