5004 BP Movement Help

Hope you can help me out! My 5004 dropped from about 4 ft the other day. Watch is still keeping time and able to wind, but there has been a strange sound coming from inside. I decided to open it up to get a better look knowing it would need to be opened and serviced anyway. The rotor doesn't spin smoothly, then when moving the watch, the rotor falls out...

1. Is this movement an in-house IWC? I thought it was based on something else that they tweaked.
2. Is there a screw holding the rotor down to the movement? Looks like a screw head on the rotor, but not sure if that holds the rotor in place or not.
3. General thoughts?
4. Ideas on repair costs?

Thank you so much in advance!

Frank

Hello Frank and welcome to the forum! You do have an in-house movement from IWC in your 5004. I am fairly confident you will require a full service and possibly a new part or two as the rotor bridge may have been damaged. I would bring it to an AD or send it in to the IWC service center in Fort Worth, TX. As Mark below states, you want to make sure you don't have any broken bits floating around inside so don't let it run until it has been serviced.

In addition to Bens excellent advice, if the rotor is loose, take it off. Then turn the watch over and hopefully the screw head, which might have sheared off, will fall out. This will avoid it working itself into the balance and escapement.

Thank you Ben and Mark! As soon as it happened I pulled the crown out to disengage the movement so hopefully the screw head wouldn't work itself into the movement. Will be near an AD next week, I'll drop it off and see what kind of damage I have caused... Thank you both for your responses!