You can't be more than 15 minutes late.
The website says you can be no more than 30 minutes later tha your ticket time
Unless you are cutting it near closing time they will very likely put you into another time slot, they have multiple lines based on entry time. Also depends on how busy it is. If there is no room, there is no room.
If you have a ticket, you may not get in if you're late. But will at a later time.
Be careful with being late though! Their official wording is that they can not guarantee entry for those who are over 15 minutes late
They should have 2 lines, one for tickets and one for general admissions. General they will cut off once an exhibit is full, but those with tickets should be ok.
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