Bird box roosting

We have a bird box and it’s been used every year by blue tits since we installed it and I clean it out over winter. I’ve decided to put a camera in there this year and was going to install it tonight before they start to use it in spring. I opened the side of the box and found a blue tit looking at me! I carefully closed the side and secured it again. Does this mean that the blue tits will no longer consider this a safe place now they know the whole side opens up and will look elsewhere for a new nest site?