Nothing happens. Walk in and sit down wherever there is room. The lights are low during the music, so a late entrance is close to invisible, and nobody will comment on it now or later.
Plan Your VisitBeing late is a normal Sunday event, particularly with kids, and it is not treated as a failure of character here. Traffic on El Camino is what it is.
If you arrive at 10:40, you have missed a song or two and you are walking into the middle of the music. That is the easiest possible moment to slip in, because the room is dark and everyone is facing forward. If you arrive at 11:00, the teaching is underway and you have missed a bit of the setup, but Ps. Sam generally recaps enough that you can follow.
Kids check in stays open after the service starts, so a late arrival does not mean your kids have nowhere to go. Someone at the door can walk you over.
There is no closed door policy, no usher who holds you in the lobby until a break, and no seat you are not allowed to take. Sit in the back if you would rather not cross the room.
Honestly, if being late is the thing standing between you and coming at all, come late. Twenty minutes of a service is not nothing, and nobody at the door is timing you.
Quick answers
Will I be stopped at the door if I am late?
No. You can walk in and sit down at any point.
Can I still check in my kids if I am late?
Yes. Kids check in stays open after the service has started.
What time does it get hard to follow?
If you arrive after about 11:00 the teaching is underway, but there is usually enough recap to catch up.