Robin nesting in garage?

Evening all

We’re having a new kitchen put in at the moment, most of which was stored in the garage. So the back door in the garage has been open all day since Monday.

Noticed tonight that a robin keeps going in and flying out as soon as I walk in. Looks like it might be trying to nest but can’t find or see anything. Found a hatched robin egg in the garden not far from the garage, so not sure what’s going on!

Any advice would be appreciated. Can’t have the door open all day going forward so not sure what the best thing to do is.

Thanks