Hello there,
as Dawn said: next time open the frames in increments- and if you live right near the hive and have the spare time- only drain a few each day and stagger the harvest over a week. When we say drain in increments- we mean you put the key into the slot say 1/4 of the way. You turn the key and then wait- I leave it for 25 minutes or more. I set a timer. then I come out- put the key in another 1/4 of the way and turn it again. And so on until you have done the whole frame. By harvesting in increments- and only a few frames a day- any honey that might spill inside the hive is isolated, greatly reduced and will not affect all of the hive at once. it will give the bees more time to lick it all up and/or move out of the way.
the next thing: Never harvest a flow hive without having everything ready! I don’t recommend harvesting directly into jars- as the chance of bees become interested, honey spills and stress are too great. The best thing to do is to get some clear tubing and a honey bucket with a honey tap on it. Make a few holes in the lid and harvest into the bucket. You can easily fill individual jars after using the honey gate. the biggest advantage of doing this is that it is bee and spill proof- and you can leave the frames draining slowly all day without millions of bees coming around to see if they can eat some of it: no bees drowning in honey that need to be fished out!
This is what I am talking about- it is very simple. I have three holes in my lid and cover any I am not using with a golf ball. In these photos you can see the two frames on the right have been drained a few days before. The two on the far left I am leaving to drain later. i am only draining the two in the middle that day: and over this entire harvest i didn’t see any spills or upset bees. I have my coreflute in the BOTTOM slot- so if honey spills it doesn’t pool on the floor and bees can’t drown in it. Afterwards I pull it out to see if any honey leaked down that far. Usually none has. Flow recommends the top slot but I don’t agree 
